36 Pontiac Surprise Gearbox Overhaul (like Buick 40)

[Bloo]

After driving my 36 Pontiac from Washington State to Wisconsin and back in late 2021 for the Pontiac Flathead Reunion, I took the generator apart because of a perceived problem. Upon getting it back together I drove to a local neighborhood store and had a brand new problem. The transmission didn't want to shift into second. It didn't grind, it just didn't want to. Thinking it might be low on oil, and not getting a reliable reading when I stuck my finger in the check plug, I decided to just drain it and change it, and compare what I drained out to the fill spec.

 

I pulled the plug  and noticed two things. 1) It wasn't low, at least not by any significant amount. 2) Chunks of metal fell out.

 

I had changed the fluid before the trip, so I knew this whole chunks falling out thing was new. The chunks looked a lot like a piece of ball retainer from a bearing. Initially that's what I thought they were. There are also "synchronizer detent springs" in these transmissions that are just long skinny steel strips. Spoiler: It was the synchronizer detent springs.

 

This post it likely to get heavily edited over the next few days or weeks as I can't find some of the pictures I intended to use. Nevertheless, there are at least two threads going right now about Buick 40 Special (5 bolt) transmissions with synchronizer trouble. Hopefully someone will find this useful.

 

Just so everyone knows what transmission family we are talking about, they have an extremely short shift tower and 5 bolts holding the top cover on. Later column shift transmissions are also closely related, and also have 5 bolts in the top cover. Transmissions of this family were used in some 30s Pontiacs, some Oldsmobiles, and 40 series Buicks. They are not related to any Chevrolets or large series Buicks.

 

Here's a blurry picture of one (not from my car).

 

 

And @Dandy Dave's broken Oldsmobile top from another thread.

 

 

Here is my transmission with the lid off, showing the internal linkage It is not really obvious how this works, I'll probably get into it deeper later.

 

 

That piece on top just lifts out, and then underneath...

 

 

The piece marked with the yellow "X" also just lifts out.

 

There are several other things to note in this picture. The holes in the red circles are not bolt holes. A ball bearing drops in each hole and a coil spring drops in on top of each ball. The top cover holds them in place. These are the shift rail detents. There are dents for the balls to fall in. One of those dents is visible circled in green.

 

On disassembly, get those balls and springs out of the holes so they don't fall out.

 

On the second gear synchro, circled in blue, you can see a little flake of brass or copper. SInce the synchro cone is a piece of heavy brass this looked out of place and like trouble.  That was sort of right and mostly wrong. More on that later. At this point I still expected to find a ball bearing retainer falling apart. Circled in purple is the tip of one of the three synchronizer detent springs. This is where the trouble lives but you can't quite see it yet.

 

To get this transmission apart the first thing you have to remove is the rear housing.

 

 

This is a Pontiac specific piece because it connects this Buick-like transmission to the Pontiac's Chevrolet-like torque tube.

 

 

One bolt removes the Chevrolet type u-joint yoke from this splined shaft. I'm not sure exactly what you would do here on the Buick. Whatever it is, it has to come off. Then the rear housing can be unbolted and rotated. Why rotated? To unhook the locking tab from this notch in the countershaft. Then the rear housing, complete with the rear bearing can come off of the splined shaft.

 

 

The tab on the rear housing locks the countershaft in place. The countershaft will have to come out a lot sooner than you might think. Why? Because the input bearing in the front cannot come out. It is blocked by the countergear. That needs to happen soon, but first let's get the shift rails and shift forks out. Undo the safety wire, and take the bolts out.

 

 

 

 

Hopefully you took the detent balls and springs out when you took the top off of the transmission. If not, and they have not rolled out the shop door and across several states, remove them now. Then the shift rails can be slid out these holes in the front, and the shift forks can be removed.

 

 

If I remember correctly the whole mainshaft assembly can probably be slid out the back. If you are used to working on modern stuff, you would probably expect a bunch of needle bearings to go everywhere when the mainshaft leaves the input shaft. It might even be true in newer versions of this transmission, I don't know. Not in 1936 though. It's a Hyatt bearing that looks like this. No needles to chase.

 

 

Mainshaft is out.

 

 

It might look like you could take the input shaft and bearing out, but no. The counter gear blocks it. You must remove the countershaft so that the countergear can drop lower in the case. Then the input shaft can come out. The shaft almost certainly has a taper, and is expected to fit tight enough to hold the oil in. It MUST be removed from the REAR of the case. Some tapping at the front with a brass drift where the yellow arrow is should get it moving toward the rear. You might once again expect needle bearings to go everywhere when the counter shaft is pulled out from the rear. Nope, not in 1936, although I think they may have switched to needle bearings a few years later. Once the shaft is out, the countergear falls a bit lower in the case clearing the way to remove the input shaft.

 

 

The front bearing cover must be removed. There is a snap ring underneath that gets caught between the front bearing cover and the case. The blue arrow points to it. Both the cover and snap ring have already been removed in the pic above. The input shaft has to come out by sliding back. the gear is too big for it to slide out the front. This picture shows the snap ring groove better.

 

 

Although it will still have the synchro attached when you pull it out, more like this:

 

 

With that out of the way you can get the countergear and it's bronze thrust washers out.

 

 

This bolt releases the shaft for the reverse idler.

 

 

And you can slide the shaft out this hole in the back of the case that would normally be covered up by the rear housing and gasket (Olds picture from the internet).

 

 

Out it comes.

 

 

Both the countergear and the reverse idler run bronze bushings on their respective shafts.

 

 

This is all in great shape so far.

 

Edited February 20, 2022 by Bloo (see edit history)

[Dandy Dave]

Looks a lot like the 1936 Oldsmobile Transmission I worked on. The piece's you found were from the flat springs? My tranny had 3 of them if memory serves me right. They're a pain to get installed correctly. Some patients and persevering and it will go together like it needs to be. Yes, these are quite a puzzle to get apart. Looks like you have a good handle on it. Dandy Dave!

 

 

Edited February 19, 2022 by Dandy Dave (see edit history)

[Dandy Dave]

These may help. Exploded view, and a part number for the flat springs. This is from an Oldsmobile parts book but from what I have seen the guts are the same. Biggest difference is the tail of the transmission. Also note, 39 and forward do not use these parts. That is when they went to 3 on the tree column shift in Oldsmobile at least. Dandy Dave!

 

Edited February 19, 2022 by Dandy Dave (see edit history)

[Bloo]

Thanks for posting that!

 

[avgwarhawk]

The gears do look in very good shape.  When I purchased my 54 second gear would grind. Opened up the transmission and found the synchro spring swimming around in the gear oil. 

[Dandy Dave]

2 hours ago, Bloo said:

Thanks for posting that!

 

Your lucky day. I had the book laying here right by the computer. Always glad to help. Dandy Dave!

[Bloo]

Hey @Dandy Dave , if you still have that Oldsmobile book handy, could you post the part numbers for the input shaft/gear, the front bearing cover, and the mainshaft? Maybe 37-38 too as well as 36?

 

Obviously the tail housing and associated parts have to be different between Oldsmobile-Pontiac-Buick because of the wildly different drivelines, but I have always wondered if the front of the transmission is different. I can post the Pontiac numbers for those parts, and I can probably get the Buick numbers too.

 

[avgwarhawk]

22 minutes ago, Bloo said:

Hey @Dandy Dave , if you still have that Oldsmobile book handy, could you post the part numbers for the input shaft/gear, the front bearing cover, and the mainshaft? Maybe 37-38 too as well as 36?

 

Obviously the tail housing and associated parts have to be different between Oldsmobile-Pontiac-Buick because of the wildly different drivelines, but I have always wondered if the front of the transmission is different. I can post the Pontiac numbers for those parts, and I can probably get the Buick numbers too.

 

I have found the main body of these transmissions are very similar if not the same throughout the years .  So are many of the gears.  

[Bloo]

At this point it is time to talk about synchronizers. Here is the 3rd gear synchro as an example.

 

 

A synchronizer is a brake. Or you could think of it as a really grabby cone clutch, the taper of which was lined with leather and used for the main drive clutch in some brass-era cars. Or you could think of it like the Morse Taper on a lathe. The synchronizer is also a taper and it is meant to grab like crazy and stop the gear.

 

You can test these on the bench. Get it nice and clean and put a few drops of oil on it. Shove the two halves together and twist. It should grab or at least drag really badly. If it does not, there is a problem.

 

I bring this up because back in the 30s it was normal to use the same gear oil in the transmission and rear axle. Hypoid rear axle gears came along in the 30s. Hypoid rear axle gears not only put extreme pressure on the drive teeth, but slide the teeth across each other as they go, wiping the oil off. This is a tough lubrication problem, and the old 600W or SAE 160 Mineral Oils weren't going to get the job done. Special hypoid gear oils were released, meant to tenaciously hang onto the rear axle gear teeth under extreme pressure and wiping. They were just barely good enough to protect the rear axle gears.

 

Now let's have another look at that synchronizer. It is bathed in oil, but it is a friction device and it has to get rid of the oil to do it's job. In this picture you can see the typical circular grooves that you might see on most more modern synchronizers (red arrow). But, there are also sharp slots carved across the face (blue arrow) to forcibly scrape the oil off. That has been done on more modern synchronizers too, but not like this. Sharp grooves are stress risers and if a modern solid brass synchronizer were cut this many times and this deep it would literally fall apart. Notice they have put a thick steel shell around this one for strength. This synchronizer is a brute.

 

 

And this is third gear (direct drive). It only has to deal with upshifts. Upshifts are comparatively easy. Second gear has to deal with downshifts too and the synchronizer is quite a bit larger.

 

Anyway, the oil must get out of the way before the synchronizer can stop the gear, and these are obviously designed to scrape oil with no mercy. As the years went on hypoid gear oil got a lot better. The science of making an oil that wont wipe off improved so much that by the 1960s it was able to protect rear axles in Street Hemis and the like at horespower levels unheard of in passenger cars in the 1930s.

 

If you are running hypoid gear oil in a synchronized transmission in 2022, you can know that the oil is doing everything in it's power to make sure the synchronizers don't work. It does everything in it's power to tenaciously cling to the taper, just like it would cling to teeth in a rear axle. Something is going to win. If the synchronizers are over-the-top brutes like these, and are in excellent condition like these, my guess is the synchronizers will win. On the other hand if the synchronizers have some wear it might not be a slam dunk. If the oil wins the gears will grind. Special gear oils made to work with synchromesh have been around since the 90s or so. I suggest looking into it.

 

Back to the transmission, you may remember that fleck of "brass" that I mentioned in the first post showing through a hole in the second gear synchronizer. I thought I might be seeing a broken synchronizer. It's in the blue circle.

 

 

As it turns out, that is a copper wave washer and it belongs there. I am not quite sure why it is there. The third gear synchronizer does not have one. Pontiac calls it a "cushion spring" and Buick says it is "used as cushion ring". As you can see, it is hosed. It's not the primary problem. It is falling apart though, and we can't have parts floating around, even if it is just copper and probably couldn't do too much damage. I'll bet this is a really obscure part, but @Kornkurt found me an NOS one.

 

 

 It fits in here:

 

 

Now let's have a look at what actually grinds if the synchro can't stop the gear. It is not the actual teeth of the gear. Those are engaged for all synchronized gears all the time. The gear has special engagement teeth that are what actually get shifted. They drive similar teeth on the synchronizer sleeve. The synchronizer sleeve drives the output shaft.

 

These are the teeth that actually do the shifting.

 

 

You can see these teeth have a little bit of a spiral cut. That is something you don't see in modern transmissions. Normally today they would be straight. The important thing is that the sides of the teeth run perfectly parallel to the sleeve or hub it drives, so that torque does not make it pop out of gear. The tips of the teeth have a special shape to them, distinct from the sides. They are pointy. In the words of the guy who taught me, the tip should look like the roof of a house.

 

 

Here is the other teeth on the synchronizer sleeve that engage this.

 

 

These are actually pretty nice. Since the teeth have a spiral cut, it distorts your view of the "roof of the house" (red arrow). When a synchromesh transmission grinds during a shift, this is what is grinding. These will always look a little abused because they take the brunt of every missed shift. Even the roof of the house can show a lot of abuse and still be fine. When the synchronizer stops the gear, the teeth might not be perfectly aligned. This pointiness causes the sleeve's enagement teeth to be able to push their way into the gear's enagegment teeth when the alignment isnt perfect. If the tips of the teeth are worn flat, or to a very large radius, the teeth will go in fine part of the time and then butt against each other and refuse part of the time. In that case, you need new parts. Another interesting thing you can see here is the polished area on the engagement teeth where they were locked into the gear's engagement teeth and under power (blue arrow).

 

One more interesting thing about the engagement teeth here is that they are reversed when compared to most more modern transmissions. Usually the engagement teeth on the gear are on the outer diameter of the taper pointing outward, and the sliding sleeve has it's teeth on it's inner diameter pointed inward.

 

Edited February 25, 2022 by Bloo (see edit history)

[Dandy Dave]

Here you are. Front cover is the Bell Housing. 

 

Edited February 19, 2022 by Dandy Dave (see edit history)

[Bloo]

Thank you!.

[avgwarhawk]

The brass wave ring acts like a thrust washer me thinks. What is the technical name of this ring?

[NailheadBob]

@avgwarhawkThe 1941 Oldsmobile chassis parts book lists: group # 4.383 retainer, synchronizing cushion part # 1286010  fits 1933 thru 1938 as @Bloo stated Buick listed it as (used for cushion ring) listed group # 4.383 under retainer, transmission gear synchronizing drum part # 1286010 fits 1934-35 40-50 series and 1936-37 series 40, from the 1950 Buick chassis parts book

 

Bob

[Kornkurt]

The parts book calls it a cushion spring.  Group 4.383 part # 553715 This is from a 1940 Pontiac Master Parts Book.

Edited February 20, 2022 by Kornkurt (see edit history)

[Bloo]

This transmission has 2 ball bearings in it, one at the input shaft and one at the output shaft. Initially I thought the chunks of metal were probably a broken ball bearing retainer/spacer. As you can see, no trouble there.

 

 

 

After extensive cleaning using brake kleen several times, soaking in solvent for hours, parts washer runs followed by compressed air, multiple times, and always oil to prevent flash rust, these ran silky smooth. Normally you would probably just replace them. Since the car does not have a lot of miles and the transmission wasn't noisy, I expected these to be fine and I went the extra mile to clean them up and verify it. I re-used them.

 

The gears had paint marks all over them. I suspected they might be timing marks. Sometimes this was done because if the number of teeth divide cleanly 6 teeth to 12 for instance, the teeth will always engage the same, and would be breaking in or wearing in a second time if you changed the "timing". Some ratios like 13:12 would engage different teeth each time they go around and it couldn't possibly matter. Some of the paint marks made sense in that context and some didn't. I doubt it matters in a manual transmission anyway, but I put them back the way I found them.

 

 

 

 

That bare gear is low and reverse. It is NOT synchronized, and to shift it actually slides and engages the drive teeth. You can see the "house roof" profile on the teeth, similar to the profile used on synchromesh engagement teeth.

 

And that brings us to the root of the problem, and why this had to come apart. Next picture is the output shaft. The left end goes in the Hyatt bearing on the input shaft. At the right are the splines where the universal joint attaches and the output shaft bearing lives. That's second gear up at the top photobombing this blurry picture.

 

 

The spiral splines at the left are what the synchronizer sleeve uses to drive this shaft. There are 6 grooves. However, the synchronizer sleeve only drives 3 of them. You can see one of the three here:

 

 

If only 3 are used what are the other 3 grooves for? Glad you asked.... A couple of things. First they drive the synchronizers.

 

 

 

And in the empty grooves between the two synchronizers are the synchronizer detent springs. I had good pictures, too of my broken ones. I even had one showing them sticking out from under the sleeve on a partly assembled mainshaft. I can't find them so for now here is an Ebay pic.

 

 

There are 3 of them, one for each groove. The little humps act as detents for the synchronizer sleeve. In use, the ends bump into the tips marked in green on the synchronizers. @Kornkurt found me some nice NOS detent springs and I replaced all three. One of mine wasn't broken, but I didn't trust it because of the wear.

 

Here is @Dandy Dave's Oldsmobile catalog picture again.

 

 

On my transmission 2 of the 3 were broken. The last 3/8" or so (yellow arrow) had fallen off and they were the chunks of metal found. They appeared to have worn through at the last bend even though there are not a lot of miles on the car. I guess metal fatigue could have been a factor as well because these bump into the tips on the synchronizer on every shift. Knowing what I know now, I would consider doing this job preemptively.

 

That brings us back to this picture again, and what you can see in the purple circle. It is the tip of a synchronizer detent spring.

 

 

More to come.....

 

Edited February 20, 2022 by Bloo (see edit history)

[Bloo]

They just tolerated some leakage in transmissions of this age. There is no front seal for instance. There are other things about the design too that aren't really 100% oil tight. Oil was thick. It did look like they used red paint they may have been using for inspection marks on some of the threads.

 

I decided to slow down the seepage as much as possible. I used thread sealer on threads, a little sealer, probably shellac on critical spots on the gaskets. There were a couple of welch plugs at the back of the transmission plugging holes probably made in the original machining of the shift rail holes. I drenched those in wicking grade Loctite, and let them soak a while. Unfortunately most of my pics of this part have gone missing. I'll probably edit them in later.

 

First the countergear and it's thrust washers have to go down in the bottom of the case, preferably in the same positions and same side up so they don't need to break in a second time. The shaft can not go in yet.

 

 

Then the input shaft and gear go in. Assemble the third gear synchronizer to it using the captured snap ring. The two keys on the snap ring go in one of the notches in the side of the synchronizer.

 

 

And then the input shaft goes in the hole in the front from the inside. Then another snap ring, the one that will eventually be trapped between the front cover and the case, goes on from the outside and snaps in the groove in the bearing.

 

Once the input shaft is in position, with the countergear and thrust washers laying in the bottom of the case, the countershaft can go in. I can't help but imagine what a pain this part would be if the countergear was full of needle bearings. I think a version like that exists. Fortunately not this 1936 version. The only thing you need to do is tease the thrust washers up into position to get the shaft started through them. That is a little fiddly but not horrible.

 

The shaft must insert from the back because it is intended to be so tight it seals. That has to involve an interference fit and a slightly different size from front to rear. Otherwise, you wouldn't be able to assemble it and still have it tight enough not to leak.

 

Then there is the matter of sealer. Designs like this aren't supposed to need it. Model A Fords are built like this though, and I have heard stories of them needing to be sealed. Since this is down at the bottom of the case, you could conceiveably lose enough fluid to do serious damage.

 

I didn't want to use Loctite, Hylomar, or Indian Head because I feared I could never get it back apart without damage. This is an extrememly tight fit with no sealer in it.

 

Chrysler has a silicone sealer meant specifically to hold back gear oil, and it is extremely effective. The Chrysler dealer was out of it and backordered with no expected ship date. I wound up with a Permatex product that is supposedly equivalent. Normally you should not allow a tube of silicone within 100 feet of any car built before the 80s. I decided to make a rare exception here.

 

With all parts hospital clean, I wiped a TINY amount on the inside of the case bore at the front, and on the shaft instead at the back of the case. Why? At both ends, the excess gets pushed outside the case, not inside. I then cleaned up all the residue on the outside. This is so tight, I doubt there is actually any silicone left in there, but if there was any void that should have filled it. Enough about that. It was likely unnecessary.

 

The countershaft must be driven in with the correct clocking and to the correct depth. You do need to plan for it. Here is what it looked like coming apart.

 

Front:

 

 

Rear:

 

 

Have the rear housing ready to test fit as you are tapping the shaft in. Use a brass drift or something else soft that will not mess up a steel shaft. If the angle of the slot or the depth the shaft is driven in to is wrong, the tailhousing wont fit.

 

The tailhousing registers in this bore (green arrow) and then you have to rotate it to engage a tab in the slot (blue) to get the bolts to line up. Don't forget the thickness of the gasket. There is a little slop in the notch to help you with this but not much.

 

 

If the shaft is not driven in far enough it could break the tab or prevent the gasket from seating right. If the shaft is driven in too far or the angle is wrong, you wont be able to rotate the rear housing to line up the bolt holes. Here is the tab (red), as seen on an Oldsmobile rear housing from the Internet.

 

 

So that is why you are checking it now even though the housing wont be going on yet. Ideally you would want the tab to drag slightly on outside of the notch so that it will get looser as you tighten the bolts and there is no interference.

 

I have probably talked way too long about this, as it will be obvious while you are disassembling the transmission. On the other hand, if it sat apart for a while it might be easy to forget.

 

Ok so now the input shaft, countergear, and countershaft are in. Now you can put in the reverse idler and thrust washers. Like the others, it would be best to get them back in the same positions and orientation so they don't have to break in a second time.

 

 

This one doesn't seal, so it just pushes in. There is a hole at the right end end of that shaft in the picture above. Align it to the hole in the case.

 

This is not a bolt (blue), it is a threaded pin that engages the hole. Put some thread sealer or Loctite on the threads.

 

 

Now the mainshaft needs to go back together. This may be brief due to my lost pictures. A lot of this has already been covered, as it is where the detent springs and wave washer were located.

 

Speaking of pictures, here is this blurry one of the mainshaft again.

 

 

And a quick recap. That is the spline the u-joint engages at the right, and the journal for the Hyatt bearing at the left. Note there is a ring or stop at the center. Second gear, no longer photobombing, is at the top. It slides on from the right side, and sits just about exactly as far left as you see here.

 

The 2nd gear synchronizer, with the copper "Cushion Spring" installed (pictured below) slides on from the left side. It attaches to second gear with a captured snap ring in exactly the same manner the 3rd gear synchronizer attached to the input shaft.

 

This captured snap ring, invisible due to my blurry picture, has 2 locating keys to engage one notch in the side of the synchronizer, just like 3rd gear. Once snapped in place, the gear and synchronizer assembly is captured on the shaft.

 

The 2 shiny dots in the splines (pictured above) just to the left of the stop are probably where the legs of the synchronizer (pictured below) were sitting.

 

Also of note in the picture above are the spiral grooves to the right of the yellow paint mark. Those interact with the oil deflector on the rear housing to limit the amount of oil going back toward the u-joint housing. The u-joint needs transmission oil to survive, but presumably this prevents it from getting overloaded.

 

 

And then the synchronizer sleeve and detent springs go on. Here is @Dandy Dave's Oldsmobile manual picture again.

 

 

That is the second gear synchro at the far right, that we have just attached to the gear and shaft. 4.413 detent springs sit in 3 of the spline grooves and then the synchro sleeve 4.414 slides on, in such a way that the deep notches clear the legs of the 2nd gear synchro. Then 4.417 slides on, all in the orientation shown.

 

That brings me to the next point. This is no substitute for the service manual or the parts book. If you are working on one of these you need it. Also take notes and preferably pictures when you take it apart, and then don't lose them like I did before I got around to posting this.

 

I bring this up because there are parts I have not mentioned. I know there is at least one more hardened steel thrust washer. I believe it goes behind second gear, but I have no picture. I believe it is 4.406 in the @Dandy Dave's Oldsmobile image below:

 

 

Now the Hyatt bearing can be inserted in the back of the input shaft/gear, and the whole output shaft assembly inserted through the hole in the rear of the case.

 

The tail housing can then be assembled and installed. This is likely different between all 3 makes, and also likely different on later Pontiacs with open drivelines. On this 1936 Pontiac though, the rear bearing goes in , a snap ring holds it in place, and the oil deflector that interacts with the spiral grooves at the back of second gear goes in.

 

This picture from the Internet is Oldsmobile, not Pontiac. I believe the bearing probably goes in the opposite side. The oil deflector looks the same. It snaps in a groove like a snap ring. You can see a notch at the bottom (red arrow) that aligns to a matching key on the oil deflector. That positions the gap on the oil deflector (blue arrow) at the top.

 

 

Then the rear housing and gasket can go on, rotate to engage the notch in the countershaft as discussed earlier, and bolt on. Use thread sealer or loctitie on the bolts to prevent oil seeping out through the threads. Then the rest of the parts on the back can go on. In the Pontiac's case that is a Chevrolet-style U-joint. The ring at the lower right lays inside, the yoke at the upper right goes on the spline and bolts on with a bolt and a huge special washer. On the 36 Pontiac, leave the small speedometer gear and bullet out for now. You will need to put oil in through the hole for the u-joint after the transmission is installed. This wouldn't apply to Oldsmobiles or 37-up Pontiacs because of the open driveline. It probably does apply to Buicks, but I'm not sure.

 

 

 

That about wraps it up at the back of the transmission. At the front, the bearing retainer can go on if you have one. 1937 and later Pontiac didn't have one, as the bellhousing doubles as the cover/retainer. I know now from @Dandy Dave's earlier post that Oldsmobiles also use the bellhousing as a retainer. I believe some of the Buicks do too. Some sealer on the studs couldn't hurt, although there is no front seal, so this probably isn't going to be completely dry.

 

 

Three things of note here: First the bearing is oiled with the transmission oil, and some flows through. since there is no seal, there is a spiral groove in the input shaft to pull oil that tries to flow out back outside back in. The hole in the retainer/cover runs with a fairly close clearance to the input shaft to help that spiral groove work. Secondly there is a drain hole in the front of the case to let any oil in front of the bearing drain back. Thirdly, there is no support sleeve for the throwout bearing like you would see on many newer manual transmission designs. You are looking at the bare input shaft.

 

 

 

Some have advocated getting a seal by using a double sealed bearing, and pulling out the inner seal so it can oil from the inside. There must be some version of this transmission that has a discrete hole you could plug, otherwise I cant explain it. As you can see, it wouldn't seal anything on this particular transmission. Every time you step on the brakes or drive downhill there will be oil ahead of the bearing just like before.

 

The good news it this groove idea works better than you would expect, and there is no seal to fail. Oil that does get out could get into the clutch, but would mostly tend to just run to the ground because there is no throwout bearing support sleeve on the retainer cover to carry the lost oil out into the clutch. That said, parking on a really steep incline is probably not advisable.

 

Here's an internet picture of a more modern transmission (Borg-Warner T5) showing the typical support sleeve:

 

 

Back up at the top, put the shift forks in place and slide the shift rails in through the holes in the front of the case. I'm not sure if the rails are different because I kept each one with it's fork throughout the cleanup process. Tighten the shift rail bolts. I put a little loctite on the threads as well.

 

 

 

Then safety wire them.

 

 

The important thing is that the hole for the pin/bolt lines up on each fork, and that the notches in the shift rails (one is visible here in green) point up toward the holes the detent balls go in (red).

 

 

Drop a detent ball in each red hole and put a coil spring on top of each one. put in the piece marked "X" Notice it is not symmetrical. Then put the other shift plate in. It isn't symmetrical either.

 

 

Put the gasket and top cover on. Sealer or Loctite on the threads of the 5 bolts wouldn't hurt.

 

I really expected the paint on this to be black or engine green. Here it is half cleaned up when you can still see some of the original paint. I believe it to be original because it was dug right into the cast iron, and there were red paint and yellow paintstik inspection marks.

 

 

More paint like that was found on the lower bellhousing pan, the inspection cover in the top of the bellhousing, and on the lower portions of the bellhousing. I guess this many years on the color might have changed, and this could have been green. I don't really believe it though.

 

 

I can't make anything out of that other than battleship gray, so that is what I painted the transmission with.

 

 

 

Edited October 11, 2022 by Bloo (see edit history)

[Bloo]

On a 1936 Pontiac, the pilot bushing in the back of the crankshaft is not a bushing, it is a Hyatt bearing! I guess this is a bit early for Oilite Bronze, although I believe Pontiac had probably already been using it in water pumps. Since you can't get to it without either pulling the engine out or the transmission and clutch out, they didn't even bother mentioning it in the lubrication chart. I knew it was there though, and that it probably had not been greased since 1936. Months or maybe years ago I bought a NOS bearing and dust cover. I had intentions of pulling the transmission out just to relubricate this bearing, or replace it if it was bad. I definitely intended to do it before the Wisconsin trip but ran out of time. I'm glad now because I would have probably stuck the transmission back in not knowing the detent springs were about to fall apart.

 

During this teardown, I decided to go ahead and do it. That meant taking the clutch out. I took the bottom pan off of the bellhousing, and disconnected one end of the clutch linkage. The linkage sits on the reinforced area.

 

 

Then the fork and throw out bearing has to come out.

 

 

Due to the tight clearance, this is a bit fiddly to disassemble. The fork must  be partially unscrewed from the inside of the bellhousing, then the step bolt can be partly unscrewed from the outside, more unscrewing from the inside, etc.

 

 

Throwout bearing:

 

 

And then the clutch pressure plate can come out. Mine had a big yellow paint mark on it that matched a mark on the flywheel. That probably means the two were balanced together, and should be reassembled in the same orientation. Watch for it.

 

Buick 40s as I understand it had a "waffle clutch" pressure plate that does not age well and is often replaced with one intended for a much newer Jeep. I don't know what Oldsmobile did. This Pontiac unit is similar to Chevrolet (I think), and is notorious for needing a special jig to set It's many adjustments properly. Out of adjustment can cause chattering. Since it looked completely unmolested, and lacking a jig, I left it as-is.

 

Since a bunch of my pictures are still missing, here is a stand in from the Internet.

 

 

Here is the clutch disc. It looks pretty good. It isn't contaminated with oil. It is thick enough according to the shop manual. This is a pretty modern looking sprung hub clutch disc, except for the fact that that the lining does not have radial cuts across the surface. They probably had not got around to doing that yet in 1936.

 

The disc appears probably original as far as I can tell, but the lining on it may not be. This is a 10 inch clutch with a 2 inch lining.

 

 

The machined surface on the pressure plate, however, does not quite have 2 inches. It falls a few thousandths short on the inner diameter, and this disc was growing a tiny sharp ridge along the inner diameter of the lining. That could conceivably cause a chattering problem. If you were picking a lining, a 10 inch lining with slightly less than 2" of material would be a better choice.

 

 

I cut the ridge off, and cut a slight bevel to slow or prevent formation of another ridge. If this lining is really from the 1930s it is asbestos, You would be well advised to not use any method that would release small particles into the air.

 

With the clutch out of the way, I could finally get at the pilot bearing. To my amazement, the bearing still had lubrication. At this point, I still couldn't find the NOS bearing and dust cover I had bought but I forged ahead anyway. After a couple of false starts with my own tools and some rented pullers from the auto parts store, I bought a tiny puller from Harbor Freight meant for pulling pilot bushings. It worked. Not only did it work, it got both the bearing and dust cover out with no damage.

 

Here they are, with the input shaft of the transmission photobombing over at the left.

 

 

I cleaned it up extensively, greased it with some good synthetic grease (Redline CV-2), put it back in and called it good for another 85 years.

 

In reality, this post is a bit out of chronological order, in the interest of keeping all the transmission overhaul stuff together. In reality I delayed final assembly of the transmission until this part was done, so I could use the input shaft as a clutch alignment tool. I do believe this most likely takes a tool that is the same as one of the common modern ones, but it didn't match any of the ones floating around in my toolbox, so doing this was probably just as quick as identifying it, waiting for one to come in the mail. etc.

 

The there was the drudgery of cleaning up the bellhousing and the surrounding area. Here it looks pretty good. It doesn't really show up in the picture but there is more battleship gray paint on it. The cover that goes over the hole was also battleship gray. The green spots seem pretty obvious later additions, definitely not original. I could not find any trace of paint up on top of the bellhousing or up the back of the engine block, only surface rust. If the engine was indeed green originally, they must have made the transition from gray to green in the middle of the bellhousing. That's just plain weird. Why would you do that?

 

 

With the pilot bearing re-installed, I put the clutch disc back in. Don't get it backwards. On a lot of rear wheel drive American cars, that means the thick part with the springs goes away from the engine. That may or may not have been the case here. The part that determines which way it has to go in this car is in the very middle of the clutch disc, the part with the spline hole. It is longer on one side than the other, and if I remember correctly that is what determines which way it has to go in.

 

Better yet, you could just take pictures when you are taking it apart. I did that, but I lost them LOL.

 

I put the pressure plate back in, aligned everything with the input shaft, lined up the yellow paint marks I found on the pressure plate and flywheel. and bolted it together.

 

Always bring pressure plate bolts down evenly. If you just tighten one you will bend something. I know most of you know that but I am going to throw it out there anyway.  Don't tighten one bolt all the way down. tighten a couple turns, turn the crank most of the way around, tighten a couple turns, turn the crank again, tighten a couple of turns. Keep going around the circle until they are all tight.

 

Now would be time to talk about the throwout bearing. It is carbon. It has an oil cup on it, and the manual suggests very heavy oil. The oil soaks through the carbon to keep it lubricated. Notice that shiny machined polished area at the center of the pressure plate. The oily carbon slides on that. That surface is a separate piece, and it is held in place by the black wire springs. It can be replaced separate from the pressure plate should it become damaged.

 

 

Here is the carbon "bearing". Note the oil cup.

 

 

I have seen replacements that have a zerk instead of an oil cup. That doesn't make a lot of sense. I suspect those zerks are really for oil just like the cup. "Oil Guns" for zerk fittings existed for machine shop tools back in the 30s. That must have been what the zerk was for, I guess. How would grease even make it through the carbon?

 

The grooves are wear indicators and this one is in excellent shape.

 

I mentioned the bare input shaft on the transmission earlier.

 

 

And the fact that most modern setups have a sleeve to support the throwout bearing like this Borg Warner T-5.

 

 

This is because most more modern throwout bearings are actually bearings. They need to be centered on the pressure plate! They slide in and out on the sleeve. The carbon bearing on the other hand is just a piece of oily carbon sliding around on a polished piece of steel. It doesn't care at all how well it is lined up as long as it doesn't hit anything.

 

I believe the Buick 40 used a real bearing originally, so I imagine it has a support sleeve. No idea about the Oldsmobile.

 

Every now and then you will see a thread where someone wants to put a real bearing in a car that came with carbon. I always wonder how they plan to center it.

 

The hole and cover plate in the top of the bellhousing allows you to put oil in the carbon bearing's oil cup if you have the toeboards of the car out. I had done it once before a long time ago, and it seemed oily, but I wanted to be sure, so I set up a hot plate out in the driveway and soaked it in in hot SAE 50 motor oil for a few hours. I then put a few more drops in the cup, and wiped it down extensively to remove excess oil.

 

I have been cautioned about over-oiling carbon bearings, apparently you can wind up with oil in the clutch. On this car though, there is no sleeve on the transmission, the carbon bearing is just hanging out in the air, and only even touches the pressure plate when you step on the clutch. I don't see how it could be a problem. I'd rather it not ever run out of oil.

 

The clutch fork, unlike most has the pivot ball more or less permanently attached. There were a couple of snap rings in there or spirolox or something.

 

 

I don't think it was meant to ever be taken apart but it is theoretically possible. I decided the chance of damaging it was too great, so soaked it in solvent, blasted with brake cleaner, etc. several times until I could no longer get any crud out. Then I packed it with synthetic grease.

 

 

The throwout bearing attaches to the clutch fork with wire spring clips. I don't have any pictures of those. I put some grease on the pivots. Now in theory the fork could go back in, and get bolted in with that weird stepped bolt and 2 lockwashers. The bolt goes in from the outside, the fork has to be started from the inside, then back and forth until the outside can be tightehed, and then the inside gets snugged last.

 

 

 

Edited February 25, 2022 by Bloo (see edit history)

[Bloo]

Before the fork could go in though, there was another little detour. There is a clutch boot. It was still there, but in shreds and covered in so much sludge you couldn't really tell what it looked like. After several runs through a parts washer in a small parts cage it was sort of clean.

 

 

The hole it goes in:

 

 

That green is not the original engine color, it is a reflection of a green tarp on the ground!

 

I figured If I did not do something about the boot, the remaining shreds would fall off and I wouldn't have a pattern. I've seen speculation that these sewn up boots were made of canvas, but not this one. This picture tells the story. It is artificial leather of some kind in brown, probably Fabrikoid or similar and probably made of nitrocellulose.

 

 

I have commented in the past about how completely unavailable this stuff is. It is quite a rabbit hole to go down on the internet. In the UK they called it Rexine, and they were probably the last to make any. Vinyl turns rock hard in the presence of oil, so that was straight out. I had a piece of brown leather, so I decided to use that.

 

With the seams ripped and the spring removed, it looked like this:

 

 

Yeah, not much left.

 

 

Here is the first pattern making attempt.

 

 

 

The first attempt was intentionally asymetrical because it looked like the original might have been. The way the fork exits the hole in the bellhousing is slightly asymetrical.

 

 

That didn't work as well as expected. I now think the original was symmetrical, and all subsequent attempts were symmetrical. Paper is a horrible pattern material for this. On this car, the boot is scrunched at rest, and stretches to almost it's open shape. It can never be quite tight because the clutch adjustment will change over time with clutch wear.

 

 

Paper patterns. Just no. It doesn't scrunch well. Subsequent attempts at a pattern were in very lightweight canvas. All the pictures of that are lost. There were at least 6 more tries at a pattern before I had something that fit the car. Then that was transferred back to paper to check the symmetry of the pattern, and cut the leather. This does have an extra 1/8" on the tabs just in case.

 

 

Here you can see the spring tied together with a twistie tie. Getting the side tabs tight at the back is tough, but very important to get it to fit right. The spring fights even when tied up.

 

 

On the original there were only 2 seams. the separate one is the little tab at the far left above. The rest of the boot was done in one run originally. It is a bit of a pain to sew around the spring with a typical industrial sewing machine.

 

I don't think it is possible to do it in one run. At some point you have to go over the spring. Judging by the stitch type on the original boot, I am convinced they did this on a bag closer rather than a normal industrial sewing machine. That might have been easier, but I still can't imagine how they got over the wire to do it in a single run without stopping the thread, but they did.

 

I did the seam at the left in the picture below separately.

 

 

Fits OK. Here it is scrunched at rest.

 

 

I wasn't planning to do anything to the clutch linkage right now, as it is easily accessed later and was still taking grease ok, but at some point it fell apart so I took it off and cleaned it out completely and regreased it. It looks like this. The piece that bolts directly to the bellhousing is not in this picture below, but it is in the picture above if you look closely. The holes at the left below bolt to the frame. This thing has a ball socket in each end. The one at the left (frame) end is held together with a spring wire clip, and the one at the right just floats.

 

 

I probably would have had to take this off anyway to get the fork connected to the linkage. That spring and washer stuff in the picture below makes the flexible connection of the fork to the linkage at the big hole in the picture above. Not shown with the springs and washers is a pin that slides in the second hole and attaches to the clutch return spring.

 

 

Ready for the transmission to go back in. The stepped bolt for the clutch pivot is tight from both the inside and the outside. You can see the carbon throwout bearing in place, and even the little spring clips that hold the throwout bearing to the fork. The bellhousing lower pan is back on. Most of the clutch linkage is too. Still not in place is a piece of clutch linkage at the far right two pictures back, and the springs and washers that attach it to the fork.

 

 

And back in it goes. The u-joint bolts back together and the torque tube bolts back up. There is shimming to do on the torque ball, but I won't go into that here. It is identical to a Chevrolet torque ball and there are various howtos online. There is also a little crossmember with a rear mount that bolts back in at this point.

 

 

Now is time to put the bottom plug in and fill the transmission with oil. I did it through the shifter hole because it's easy. You also have to put some oil in through the speedometer gear hole for the u-joint. I did that and put the speedometer gear back in and hooked the cable up. Chevrolet style u-joints need to be lubricated. In normal use enough oil will get back there to take care of it, but on an initial run after a rebuild like this, or on a car that has not been driven in years, the universal joint can destroy itself in a very short distance if you do not put oil in there! Don't forget. I suggest using a synchromesh friendly gear oil in a synchromesh transmission. There are quite a few options now. I am using Redline 75W140NS synthetic in this car. Note the NS. The version of this oil without the NS in the name is not synchromesh friendly.

 

 

More to come.....

 

 

Edited February 24, 2022 by Bloo (see edit history)

[Bloo]

That leaves the shifter. I had no intention of tackling this. It was all sloppy but not really causing any trouble. The "fulcrums" are what supposedly wear out, but I had this apart once before in this thread. I was installing a new floor mat just before the WIsconsin trip.

 

 

I had already seen all my parts back when I posted that thread, and knew they were all shot. I bought this NORS kit on Ebay.

 

 

 

 

 

All the Pontiacs on that list don't even use the same family of transmissions. Some are Chevrolet Master based, and are completely unrelated. The manufacturer apparently had no idea what these parts fit.

 

Still, it looked like the right stuff, and looked much better after a dunk in evaporust, they look pretty nice.

 

 

The "fulcrums" (the big round parts) are usually what is shot. Mine were so shot the shifter had started to wear through the springs (at the bottom of the picture above) too.

 

This is what happens to fulcrums:

 

 

Now here is the problem, the pin in the shifter runs in "hole" formed by the two half moons in the edge. The pin in the shifter is too big. It will never fit in the transmission lid like this.

 

 

There are 3 major differences here, and 2 of them do matter. First, The hole is the wrong size. Second, the pin on the shifter is not only too big in diameter for these fulcrums, it is also too short. It barely catches the hole. Thirdly, the fulcrums are deeper. The extra depth doesn't matter though, because there would be enough room if the pin fit the hole.

 

I ground out the "hole" until it fit the pin, but then the pin was still too short. I then went into blacksmith mode and hammered them a bit to force more of an oval shape (blue arrows, first picture). That caused the corners (red circles first picture) to lift. Since I had to pound them down a little I decided to keep going and make them touch the square area on the shift lever (see one picture back). I doubt these were ever meant to touch, but it takes strain off of the pin and the "hole" it runs in, so why not?

 

All this pounding brought the holes in the side (blue arrows second picture) into an oval shape. I also had to keep tapping to keep the surface (yellow arrows second picture) flat. I had to flat file them a little to get them back perfectly flat. At this point the pin fit the fulcrums nicely, the ends of the corners were touching to take the strain off of the pin, but the end caps (purple second picture) needed to fit in the holes (blue arrows second pic). I had to grind the holes that had become oval round again with a dremel tool.

 

 

 

 

The result was excellent with the shifter, so I guess I don't regret buying these parts, but for all the time it took, I probably could have welded and ground on my old fulcrums enough to fix them. I still would have needed the springs (bottom of the pic above) because the old ones were worn about halfway through.

 

One thing that seemed ambiguous the last time I had the shifter apart was which way the tails of those springs go, up or down (bottom of the pic above).

 

In that old thread I linked above @DonMicheletti said "At the end of the day. the stick should be spring loaded toward the second / third position".

 

That solves the mystery. One tail goes up and one tail goes down. It has to be that way now that there is not a half inch of slop in everything. That narrows it down to two possibilities, and only one of the two possibilities spring loads it toward second / third.

 

Back together it goes!

 

 

More to come.....

Edited February 25, 2022 by Bloo (see edit history)

[NailheadBob]

@Bloo, you did an excellent job, description and photo's made this more enjoyable to follow, Pete Phillips has the Kent-Moore/Hinckley Meyers special tool number J-1129 that sits inside the frame/floor of the car with a cable to winch the transmission up slightly for removal rearward and then lower it down to the floor.

 

Bob

[Kornkurt]

I have the parts you bought in the NORS kit in NOS, genuine Pontiac in case your post gets anyone else in the mood to fix their sloppy shifter.

[Bloo]

All done, and my new (right before the Wisconsin trip) floor mat finally back in. It's a cut down unpunched 1937 Buick 80 mat. Not a bad fit. Not perfect but not bad, and can probably be made a little better with slight modifications to the padding. That bit at the back that doesn't quite lay down is under the seat.

 

 

With the car back together I headed back out on the road to test the generator and visited some little towns around here, and that wrapped it up 2021. I tacked that on the end of the WIsconsin thread here. https://forums.aaca.org/topic/368054-road-trip-pontiac-flathead-reunion/page/3/#comment-2333762

 

For reference, I thought I would post some the differences that allowed these transmissions to fit various GM makes. Thanks to @Dandy Dave, @NailheadBob, @Kornkurt and @37_Roadmaster_Cwho provided part numbers that made this possible. This is mostly about 1936-38, and is by no means exhaustive. I believe transmissions with the odd short monkey motion shifter as seen in this thread probably originated at Oldsmobile, maybe even before 1930. By the mid 30s, they were coming primarily if not entirely from Buick's Flint plant, or at least reading about the strike at Chevrolet's Toledo plant would lead you to believe that.

 

Here is a look at the differences between versions at the back, in the interest of helping ID these transmissions easily. Everything at the back is different on the different makes, we know they had to do that to get them in the different cars. This chart looks mainly at the output shaft because it is the only part at the back that reaches inside the transmission. Were they able to use the same output shaft on different versions?

 

Differences at the back of the transmission:

Make          Year       Driveline             Speedo Gear    U-Joint Type      Output Shaft
---------------------------------------------------------------------------------------
Buick 40      1934-36    Buick Torque Tube     (?)            Buick Enclosed     1287295
Buick 40      1937-38    Buick Torque Tube     Above Shaft    Buick Enclosed     1298002
Buick 50      1934-35    Buick Torque Tube     (?)            Buick Enclosed     1399606

Oldsmobile    1934-38(?) Open, Short Tailshaft Above Shaft    Open               (?)

Pontiac       1935*      Chev. Torque Tube     Below Shaft    Chev. Enclosed**   1287295
Pontiac       1936       Chev. Torque Tube     Below Shaft    Chev. Enclosed     1287295
Pontiac       1937       Open, Long Tailshaft  Above Shaft(?) Open               1300025

*Late 1935 ONLY
**Rear housing is 1935 only, transmission mount location probably differs from 1936

 

As it turns out, Yes. The 1934-36 Buick output shaft was also used on the enclosed driveline Pontiacs of late 1935 and 1936.

 

This means they could have produced the Pontiac transmissions, the back half of them anyway, by just using different external parts. I don't know if they did, but they could have.

 

And now the front. Were any of the input shafts the same across makes?

 

Make        Year        Front Bearing Cover    Trans Case                Input Shaft/Gear
----------------------------------------------------------------------------------------
Buick 40    1934-35*    (none listed)          1285520 lhd 1286317 rhd   1282454
Buick 40    1935 late   1289436**              1294297 lhd 1395653 rhd   1282454
Buick 40    1936        1289436                1293153                   1282454               
Buick 40    1937        1289436                1293153                   1298000
Buick 40    1938        (none listed)          1305765                   1394770***             

Buick 50    1934-35                            1280425 lhd 1283200 rhd   1282454     

Oldsmobile  1934-36     (uses bellhousing)     (?)                       1284271
Oldsmobile  1937-38**** (uses bellhousing)     (?)                       1298738
Oldsmobile  1938****    (uses bellhousing)     (?)                       1300487      

Pontiac     1935*****   1293296                1395781                   1293298
Pontiac     1936        1293296                1399802                   1293298
Pontiac     1937        (uses bellhousing)     1293596                   1298738

*early 1935 only   **none listed early 1935   *** mentions included oil seal    
****with footnotes (probably early and late 1938?) *****late 1935 only

 

As it turns out, almost none. The 37 Pontiac uses the same input shaft as the 37-38 Oldsmobile. Both use their respective bellhousings as the front bearing cover.

 

Of course none of this is really conclusive evidence. Part numbers for the same part are not always the same between divisions, but fairly often they are.

 

Versions that use the bellhousing as the front bearing cover would have no stud holes at the front bearing, so that's an expected difference.

 

EDIT: One more difference, thanks to @pont35cpe , I now know that the Buick input shaft has a 1-1/4" spline. I measured another 36 Pontiac transmission, and the input shaft has a 1-1/8" spline. The clutch pilot on the Pontiac is about 0.590", but that may not be an exact measurement.

 

Now here are numbers for the parts that were actually bad in my transmission...

 

Cushion Spring

Make          Year      Group    qty/car   Name in Parts Book                Part Number
----------------------------------------------------------------------------------------
Buick 40*     1934-37   4.383      1       Used as Cushion Ring              1286010
Oldsmobile    1933-38   4.383      1       Retainer, Synchronizing Cushion   1286010
Pontiac       1935-37** 4.383      1       Cushion Spring                    553715 

Synnchronizer Detent Spring

Make          Year      Group    qty/car   Name in Parts Book                Part Number
-----------------------------------------------------------------------------------------
Buick 40*     1934-38   4.413      3        Spring, Synchronizing Detention  1300501
Oldsmobile    1934-38   4.413      3        Spring, Synchronizer Detention   1300501 
Pontiac       1935-37** 4.400      3        Spring, Synchronizer Detent      1300501

*also Buick 50 1934-35  **late 1935 only

 

Edited March 8, 2022 by Bloo (see edit history)

[Bloo]

Hopefully some of the following helps identify any loose transmissions.

 

Buick, showing the stout torque ball used on Buicks because the torque tube acts a fore-aft suspension location member. (This is a picture posted by @70sWagoneers in another thread).

 

 

Oldsmobile, showing the short tailshaft and u-joint flange for an open driveline. (This is a picture  @Dandy Dave posted an another thread):

 

 

Late 1935, 1936 Pontiac. Oddly I don't have good pictures. Here is the side view of  my 1936 from earlier in the thread showing the distinctly Chevrolet-like rear housing. Speedometer drives from below the shaft.

 

 

But I don't have one from the rear with the u-joint installed. The 1936 rear housing is 1293575 (Late 1935 is probably 1299299, not sure what the difference is. Possibly the position of the transmission mount boss).

 

 

1937 open driveline Pontiac with the long tailshaft. The long part of the tailshaft is removable, leaving a small rear housing on the transmission. The only pictures I could find had the rear part of the tailshaft removed. Look at how long it is! (These are pictures @m.navarro posted in an old thread):

 

 

 

And another pic I found online showing what you see at the back when the tailshaft is off but the rear housing is still on (transmission on the right):

 

 

 

Edited May 17, 2022 by Bloo (see edit history)

[EmTee]

Excellent article -- I almost feel like i could give it a try if I had to...

[Kornkurt]

John, So that now you have your transmission fixed, what's next?  Engine overhaul or higher speed rear end gears?  I'm still worried you will get a ticket for obstructed view with that cloudy glass.

[Bloo]

I found myself a little buried when I got home, and that is why I am just getting around to posting all this stuff from late 2021. That glass is on the list to get replaced, and I already have a new gasket, but I am 6'3" and it doesn't obstruct anything. Next thing to tackle I guess will be to pull the head and look at the bores. The high speed gears just need to be put together. It is still winter here and the car is put away. I Imagine I will do the gears first, because the shop manual is pretty picky about how they are to be broken in, and I would like to get it overwith.

 

Edited February 26, 2022 by Bloo (see edit history)

[Kornkurt]

What axle ratio do you have, and what are you changing to?  

[Bloo]

I have 4.89 (Pontiac mountain gears) changing to 3.82.

[37_Roadmaster_C]

@Kornkurt,  I will start beating on him with wet noodles to get him to do what he keeps saying he wants to do. We get together for lunch several times a week so I can apply LOTS of noodle lashes in short time...  On a serious note... Johns work and knowledge is amazing. I wish I had half of it..... I don't 😢.

[Dandy Dave]

12 hours ago, EmTee said:

Excellent article -- I almost feel like i could give it a try if I had to...

Not that bad to do. Just need to get all the pieces back in in the right order and at the right time. Dandy Dave!

[Ben Bruce aka First Born]

9 hours ago, Bloo said:

I have 4.89 (Pontiac mountain gears) changing to 3.82.

That should drop about 500 RPM!

 

  Ben

[EmTee]

10 hours ago, Bloo said:

I have 4.89 (Pontiac mountain gears) changing to 3.82.

It must be a terror at the dragstrip! 

[37_Roadmaster_C]

19 hours ago, EmTee said:

It must be a terror at the dragstrip! 

I'll put it up against the Roadmaster IF he ever gets the gears in it 🤣.

[DonMicheletti]

When I was a kid, there was a guy who ran a '38 Buick Century at the drags in a "stock" class. He would clean house.

Of course, just like the other "stockers", he was cheating like heck. You can do a lot to the Buick engine that cannot be seen.

[Bloo]

11 hours ago, 37_Roadmaster_C said:

On 2/26/2022 at 6:32 AM, EmTee said:

It must be a terror at the dragstrip! 

I'll put it up against the Roadmaster IF he ever gets the gears in it 🤣.

I can't help but think of a story I heard Pete Lovely tell. Pete was a Formula 1 driver for Lotus in the 1960s. He was talking about his very first sports car race, around 1949 at the old Bremerton Raceway in Washington State. Pete entered a Renault 4CV, and came in so far behind there was some question about how many times he had been lapped. When he went to get the final results, the race marshals were arguing with each other because they couldn't believe anything was that slow.

 

 

Edited February 27, 2022 by Bloo (see edit history)

[TerryB]

Absolutely great write-up.  The shop manuals never go into this level of detail and with as many photos to go along with it.

[pmhowe]

I don’t own a Pontiac. I don’t own a Buick. I don’t own an Oldsmobile. However, this was a fascinating thread. Thank you for posting it, and thank you for the thoroughness of the explanations and the excellent pictures. This thread taught me a lot.

Phil