dynaflow just blew low

[downunder pat]

well geday everyone merry christmas seasons greetings .Well i brought a 55 century about a year ago but it took a little bit of time money to get here on the road witch it is now on here third day .The dynaflow was reccoed in usa one year before i brought it .Anyway two things i love driving with dynaflow (i think im addicted) and low speed gave up up on short but little steep incline(my own driveway).I did notice just before i went up driveway that once low was selected it did take a second or two before it engaged .Then once going up hill slipped then spat out tranny fluid i think out of dipstick stopped ;im not asking any one to use exray vision or anything but live in austraila and information in short supply.I have probably broken the band and will have to get another but if say the band should be installed in a certain way ect or it will happen again.or do dynaflow not like hills .It still runs in drive i love it.any information would be appreceiated.

[Bhigdog]

You might have blown the low accumulator gasket.......

[JohnD1956]

If it still goes in Drive, then I don't think you have blown a band. This sounds like an external leak like Bhigdog says.

I would like to say I never broke a dynaflow but can't. My 1st 56 lost reverse by dropping it into reverse while I was holding the throttle in a higher than idle RPM range. This was due to the engine being cold and I tried to back out of a parking space into heavy traffic. No more reverse at all.

Do you have a Service Manual on this car?

JD

[downunder pat]

Thank you JD for your reply. yes i do have a work shop manual(because according to manual there should not be any issues with these boxes ).So with your reversing dropping out i noticed you said higher than idle speed .do these boxes have to be treated in a certain way ect.Or is there an old article somewhere where i can educate myself a bit.I imagine that this may be a frequently asked topic regards Patrick Maiden

[Rooster]

If you have not already , I would strongly suggest you join the BCA ( Buick Club of Australia )to assist you with Buick problems, comradeship ,outings etc. and to put you in touch with a an auto trans expert. There are some here in OZ but you have to find out where eg. BCA members.

There are sections in Qld, NSW, WA, & Vic.

I can't help you with Dynaflow as I have recently bought one myself and am still learning about them.

What state are you in ?

[downunder pat]

Thank you ken for your reply.Yes iam a member of BCA nsw.But no one from NSW seems to realy know (that i have talked with) .There have been two people sugest someone in QLD but that about it realy.There dose not seem to be anyone with knoledge,on these trannys.If you have 56 you would also be running a 322 ci same as me.how dose yours pull up steep hills.

[Rooster]

Give Phil Green a ring 03 93112049 . He has restored a few cars of late. He might be able to suggest who to talk to.

My 54 has a 322 engine but I have not had it long enough to put it through any different road conditions.

[50jetback]

Both Phyll Green and Owen Manford from the NSW Club have had Dynaflows rebuilt, either should be able to put you onto someone to talk to over there.

[JohnD1956]

Here's what I can tell you. Even though it says Dynaflow, you are correct that it still has bands for gearing. The tranny is supposed to be very simple, but I have never rebuilt one of these or any tranny so I can't vouch for that.

The 54-55 and 56 I think all have various differences that account for different performance. Certainly the engine Horsepower outputs were different so you really cannot equate any of these three together for performance.

As far as transmission idiosyncracies, I can tell you that I always try to warm my car up before switching to any gear. By warm up I mean when I can get it to step down from fast idle. I also note that left unused for 30 days will cause a transmission leak which I believe is draindown from the torque converter and then seepage past the rear seal. Driving the car every two weeks seems to be enough to control this problem. Some much better mechanics than I have actually fixed that rear seal and stopped it from leaking. I have not had that pleasure yet.

Once the transmission is two quarts low, the car feels like it is dragging an anchor. Put those two quarts back in and it runs like new.

The transmission has several seals which can be replaced without pulling the transmission. This is good because that transmission weighs as much as a small house. If you have to pull the tranny, the torque converter does NOT seem to pull off like newer ones. I believe it has to be disassembled in place to get it off. For assembly purposes there is a ring of small bolts around the front of the torque converter. 4 of these serve as the attachment bolts for the flywheel. Just to get the tranny out of the car you only need to remove these 4 bolts, not the rest of them, and drop the tranny with the torque converter in place.

As for performance, I can only attest to the 56.

When mine is running on flat ground at thruway speeds it gets better than 18 MPG. That's the best it will ever do. Other than that it will run between 12 and 16 mpg depending on what driving conditions are. I have driven my car to Flint Michigan from my NY home on 3 different occasions. I feel very confident that this tranny could take my car across the USA and back with no problems.

The 56 has a dual pitch stator in the torque converter which gives you some better off the line performance. I would not try to burn rubber with the car but it can get up and move out rapidly considering the cars age and weight. It will not beat much off the line but the performance is surprisingly peppy.

The 56 also uses a cooling unit in the radiator like most modern cars. The 55 uses a different cooler which is mounted under the car by the rear transmission mount.

The car will clunk going into gear after it has been used and warmed up for a few miles. Several things can cause this. On being a broken rear tranny mount. That is a two part mount meant to take up torque from 4 directions. They may look like they are together but that iu because the weight of the tranny is crushing it. It always pays to have that mount checked to make sure it is together.

The other thing I was told, by an old time mechanic, is that there is a felt washer at the rear of the driveshaft, which will compress and distinegrate. I have no first hand knowledge if this is true or not. All I know is I have two year old motor and transmission mounts and when I first start the car I get no clunking, but after I drive for a bit it will clunk going into reverse. It has always clunked on me and thats why I try to get the engine RPM down as far as I can before shifting gears.

You may have noticed that the manual calls for a 450 RPM setting. This is no joke. The nailhead can do this and you can't even hear it running.

[Guest wayneMP]

Just read about your troubles. While I don't have a magic answer for you. You might find the following address of some interest. Cheers and good luck!

http://www.55buick.com/dynaflow/dyn2.html

[buick840]

Pat??

Hi from a fellow BCA member in Victoria and welcome to the Forum

If you have no luck in finding some answers from Phil Green send me a PM or email me and I will give you a contact number for a guy in Melbourne who has a very good knowledge of these transmissions and has rebuilt quite a few with good reports from the owners.

Hope you have luck with your quest and keep us updated.

Also as the message to the left requests it would be nice if you could please post your name as it makes it much more personal to be able to chat with someone knowing their name not just a "Handle"

Best Regards

Brian Flynn

buickman@bigpond.net.au

[Rooster]

John , please tell us which seals can be got at and replaced without pulling the tranny.

My 54 has a few leaks and while I've got the rear end out I can check things out under there.

Cheers.

[JohnD1956]

I want to go back to my manual and make sure i call this right before replying. In any case my response will concern the 56 transmission.

JD

[downunder pat]

Firsty thank you to all who replied to my question .I will contact brian regarding contact(i just want to fix it once if possible)

If any one is interested i have brought from states a electric wiper motor and switch 2 speed with intermitted and delay /washer botton have not installed yet it is meant to conect to standard vac switch? will let you know how well it works ? or if you have one might let me know how it fits on standard switch. made by newport engineering usa.Also for any 55 owners in aus i was offered rear fender skirts /spats fiberglass $280.00 au but did not like look but maybe some one else whould.

regards Patrick Maiden BCA nsw #991 jmaiden@iprimus .com.au

[JohnD1956]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 29 tourer</div><div class="ubbcode-body">John , please tell us which seals can be got at and replaced without pulling the tranny.

My 54 has a few leaks and while I've got the rear end out I can check things out under there.

Cheers. </div></div>

First off I want to say Happy New Year to everyone.

I just finished reading my 56 Service manual and would like to respond to this request. Before doing so I want to make it absolutely clear that I have never taken one of these things apart, I am in no way to be considered a authority on this transmission and what I am relaying here is my understanding of the 1956 transmission. Also this post will be lengthy, but not comprehensive. I am just trying to help here and if I called this stuff wrong I would most heartily endorse corrections. I'd like to be sure what I read was right too. so here goes:

<span style="text-decoration: underline"><span style="font-weight: bold"><span style="color: #FF0000">Dynaflow operations</span>:</span></span>

Dynaflow movement is a mixture of operation of a direct drive clutch or application of a low or reverse band. When selected, the low and reverse bands are stationary against their drums, however, in direct drive the bands are not in contact with their drums but other parts of the low and reverse gear set become applied and form part of the direct drive clutch.

Therefore it is possible for direct drive to propel the car forward while the band for low is broken and inoperable when selected. However there are other parts of the low operational controls that may be suspect when low itself does not operate.

When selecting low range, the transmission oil passes to the “low servo”. In the process the low accumulator ( an external valve between the bell housing and the transmission on the passengers side of the car ) serves as a reservoir of oil to cushion the shift into gear and then the shift from low range to direct drive. When activated, the servo is connected to a pivot ( called “band operating lever”) and the other side of this pivot is connected to a “strut”. The other side of this strut is connected to one side of the low band. The other side of the low band is connected to a 2nd strut which is fixed to the transmission case. When selected, the servo pushes up on the pivot which in turn pushes the 1st strut to close the gap in the band against the fixed side of the band, which makes the band stationary for low to work. The servo is in the valve body on the bottom of the transmission.It appears these struts may be just above the valve body but don’t quote me on that.

Anyway, isolated failure of low range alone could be in the servo, in the struts, or in the band itself.

The valve body may be removed while the transmission is in the car. However the book advises the first thing to do in any diagnosis it to ensure there are no external leaks of tranny oil and to make sure the shift linkage is properly adjusted. There is an external linkage adjustment. However if this is unsuccessful in correcting the problem, then there is an internal linkage adjustment that should be employed.

Other interesting facts:

* The torque converter contains the front oil pump. There is a rear oil pump too.

* the oil capacity is sufficient to completely fill the torque converter “while in operation” plus “approximately 3 quarts for lubrication and operation of all hydraulic controls.”

* The direct drive clutch is activated by certain amount of oil pressure applied directly to the unit.

* The rear oil pump comes into play as the car moves and completely takes over for the torque converter when reaching speeds of 45 MPH. However the torque converter remains filled with oil during operation. ( thus low oil reserves may severly impacts operation of hydraulic controls.)

* The following external seals can be replaced while the transmission is in the car.

Low and reverse adjustment hole covers

Oil dipstick filler

Rear bearing retainer at the flanges, cross-shaft bearing, and torque ball.

High and low accumulators at the cap, plugs, and body.

In addition the valve body can be removed while the tranny is in the car.

Other seals will require removal from the car.

Any parts removed should be thoroughly inspected for disintegration of their gasket, this includes the valve body.

For purposes of responding to the original post here, I would try to purchase a valve body gasket and oil pan gasket. But before tearing into the tranny I would check that low accumulator for leaks against it's mount. You may get lucky with that fix. Otherwise I would check those struts that attach to the band. Note that reverse also has these struts, so if you do not have a manual, leave it alone till you have definitive documentation of how to proceed. At least the car still moves now.

Good luck

[old-tank]

Does Reverse work in addition to Drive?

[downunder pat]

Firstly happy new year and god bless to one and all.Thanks to JD1956 and old-tank for your replies.especially jd for takeing the time.I think all information gives me a clearer picture of the over all. Old tank yes it dose go in reverse.

This is what i think may of happened .Two years ago tranny rebuilt,but rear torque boot and cover was not replaced at time of this work been carried out(i just had this done) witch tells me that owner and transmittion shop were not familiar with dynaflow .Through looking at suppliers sites about tranny parts i noticed that it seems to require three different orders to fully rebuild unit firstly what is said to be tranny reco kit ,secondly band replacement ,thirdly torque boot and seal.Even though i only have a docket to say unit was rebuilt and when under car it seems obvious that tranny was pulled out and cleaned ect,and it drives too well in drive.But i am suspect that bands and struts may not have been done as with the torque ball seal and boot.

Whitch leads me to ask the questions.where do i obtain the parts to rebuild both low speed and reverse bands /struts?and the other parts that jd1956 mentioned.One supplier cant remeber

whitch one was exchange only but i dont understand as i think these new band are ment to be stronger than factory.Can i buy the improved parts outright and whitch supplier ?

Any advise would be apprecicated.

regards Patrick Maiden Buick club Australia (nsw)

nu#991

[Bhigdog]

Try FATSCO. The bands and all parts are available. The replacement bands are stronger. Bands are usually exchange only but you might find them outright with a hefty core charge........Bob

[old-tank]

Patrick

Hopefully you find a good tranny man that has seen a dynaflow before...who starts with an external inspection of the accumulators (still might be a blown low accumulator gasket as Bob suggested), pressure checks as outlined in the service manual; inspection of the valve body including the low servo and pressure regulator; then inspection of the low band lever and strut. One other test you can do is to see if low works AFTER the car has been in motion in drive...shift to LOw at 15 to 20mph.

I had to do R&R on a dynaflow 4 times and I don't wish that pain on anyone. Even though it 'may' have to be removed you can narrow down the source of the problem...maybe even repair without removing.

Willie

[downunder pat]

Thanks old-tank for your reply .I did as you suggested shifted to low at around 15 to 20mph but no engagment.dose this suggest anything to you Willie.

regards Patrick Maiden Buick Club Austraila *991 nsw

[Rooster]

Just got my torque ball retainer kit from FATSCO in the mail today.

Can't wait to unpack it and install for a leak proof, hassle free , drip proof , no worries mate ------solution

Get one Pat !!!

[old-tank]

Patrick

At 15-20mph the rear oil pump is supplying pressure, but apparently no help there.

Check out this site

for 56 specifics. Even if you don't do the work on the tranny yourself, you can get a good understanding to ask the right questions and be sure the answers are not BS.

Willie

[JohnD1956]

Continuing to read up on the 56 Manual I found out this, from my previous post, is wrong; "Other interesting facts:

* The torque converter contains the front oil pump. There is a rear oil pump too."

The front oil pump is not in the torque converter, it is in the front of the transmission case in the part that holds the two accumulator valves.

After reading my manual more I hope I did not simplify things too much with my prior post. One time I had heard that there were only six moving parts in a dynaflow but obviously someone was just pulling my leg on that one. There's a lot of gears and moving parts in here. But the fact that your car goes forward in direct drive indicates most of it ought to be okay.

As suggested above, the primary thing to do is check for an external leak by that passengers side accumulator. As you originally posted, the tranny spat fluid from the dipstick tube area. The low accumulator is right behind the dipstick tube. That accumulator will only be filled with fluid while the car is in low. So you have to have a partner here to idle the engine and put the car in low gear while you look under there. It seems you also have to raise the engine idle a bit, no more than 1K RPM. Remember, the engine is supposed to idle at 450 RPM. If you see a leak at all, this must be fixed before further diagnosis. If you have a local service station with a lift that suspends the wheels, I'd take the car there and ask them to raise it up and run the engine up while in low gear. Watch out though for spraying hot oil. If I read the book right, that circuit will be under 200 lbs pressure when selected.

If that accumulator is leaking a lot then it's likely you'll never get enough pressure or volume to activate the servo that tightens the low band and brings it into play.

The good news is the accumulator can be removed while the transmission is in the car. The bad news is on my 56 it looks like it's made of aluminum, so I'd be real careful handling it and I'd check it carefully for cracks or external damage.

And once again, all this refers to the 56 tranny, and it may or may not apply to your 55 tranny.

I hope you can sort this out and get her back on the road. I definitely would not be thinking major rebuild here since the car does move forward and reverse.

[rmartens]

On my '56 the accumulator is held on by 4 bolts, IIRC. I thought it was a cast piece--don't recall it being aluminum, but I may be mistaken.

Both accumulators and the front end of the transmission share a gasket, IIRC--but with caution, you might be able to fabricate one just for the accumulator.

I've (unnecesarily, it turned out) dropped my Dynaflow and pulled it apart and put it back together without major difficulty. You will need a gasket kit at minimum, but replacing the low band should not be all that challenging if you have a clean workspace with good lighting.

Either the accumulator or the main body of the tranny has a plug where you can check for the proper pressure. I purchased a decent gauge, and found a flexible grease gun hose that fit the tranny port exactly and the gauge with an adapter. Check pressure first!

[Rooster]

This is all good stuff.

I'm learning a lot here.

[JohnD1956]

That's interesting. The manual indicates the accumulator bodies could be a cast metal. It says to check it for cracks. Aluminum probably would not just crack.

It also says that the accumulator bodies can be removed separately without the transmission coming out of the car. The part they are attached to is called the "reaction shaft flange" And this is in between the transmission case and the bellhousing. There-for the torqueconverter and bell housing would have to be removed to replace the gasket between the flange and the transmission case.

The accumulators sort of hang off the sides of the "Reaction shaft flange" but their gasket surface is in the same orientation as the flange's. I wonder if the entire gasket is stamped as one piece but intended to be disectable so as the accumulator portions may be cut off and used separately?

Anyway, the manual shows five ports for testing oil pressure of the transmission and calls for the oil pressure tests to be done in the following order:

1st the front oil pump. 2nd the rear oil pump, 3rd/ 4th the high or low accumulator, 5th the end of the reaction shaft flange.

The tests are to be conducted with the engine warm and at three RPM Speeds , 500, 1K and 1800RPM engine speeds. The rear wheels need to be free to spin off the ground as the test process calls for testing in all the gear ranges.

The values are laid out in a chart which I will try to re-create in a separate post. The results are discussed in relation to diagnosis and this is just too much to relate here. I would note however, that the only defect not discussed is the car failing to move in low.

What it does say is low pressure at the low accumulator may be caused by:

External or Internal leakage past the accumulator body gasket.

or a restriction or plug in the accumulator's metering orafice.

Since this is looking more and more like a Low Accumulator problem, not a band, the oil pressure range at the accumulator for Low Gear is as follows:

500 RPM 115 lbs

1000 RPM 175 lbs

1800 RPM 175 lbs.

As indicated above the port for this test is right on the low accumulator body. If you do not have an external leak you should run this test alone. Failure to get these oil pressures may still be fixed without transmission removal.

You may notice I'm in favor of leaving this transmission in the car. I've been under two of these in my life time, and know they are HEAVY. If it has to come out it's gonna cost lots of money. So if at all possible, leave it in the car.

JD

[Rooster]

In reference to your last sentence John, now you're talking my language.

So reading above, if I take off both the accumulators I just trim off and around the existing flange gasket, then make up new ones just for the accumulators and bolt back up ?

[JohnD1956]

The photos of the accumulators themselves shows an interesting configuration. Also on page 5-63 in the 12th step of section f of the manual, it says to "place accumulator gaskets in position so the holes match the holes in the reaction shaft flange." If I was trying this I'd see if I could get the correct prestamped gaskets first.

It also says to coat the bolt threads with Permatex No.3( non hardenening.

It shows assembly of the accumulators as part of reassembling the entire transmission. From this perspective it designates a tightening sequence to the bolts. I presume if you just remove the accumulators then the entire sequence is not a major issue, however on the accumulators ( which are both at the end of the sequence) it shows 4 bolts. The sequence on both is the upper inside bolt first. The lower outside bolt second. The upper outside bolt third and then the 4th bolt to finish up. It shows the high accumulator before the low one but in this case I don't think that will matter.

It also says tighten to 5 ft lbs first, then to 20-25 ft lbs, then 40 to 50 lbs on these accumulator bolts only.

Note also: the high accumulator has a retaining pin and check ball. The low accumulator does not have these parts. Make sure they are in there before returning the high accumulator to the Reaction shaft flange. I don't think I can describe how they are located inside the accumulator body except to say if you be careful not to flip the unit around to much chances are they will not dislodge unless you specifically remove them. I'd be much more comfortable with this if you reviewed the manual first.

And as always, I'm talking a 56 transmission. I cannot be sure other years are exactly the same.

Good luck.

[rmartens]

If in fact the problem is isolated to the low accumulator, there should be no need to mess with the high accumulator.

If you do not have a manual, Budd has many pages scanned in on his website for 1956. Mr. Earl lent me some Dynaflow-specific info a couple of years ago and had me forward them to Budd when I was done, so there is a good bit of material there.

http://www.agentbudd.com/56Buick/index2.html

If at all possible--check pressures at all possible ports in all shift positions BEFORE removing the transmission. Your problem could also be in the valve body where pressure is directed by the shift control to the low band and accumulator. I believe the valve body CAN be removed with the tranny in the car.

(If you do end up pulling the tranny--after reassembling mine, I was able to use a large socket, pieces of 1/8" rubber, hose clamps, and duct tape to use a 1/2" drill to spin the torque convertor and check all low rpm pressures on the bench.)

[Bhigdog]

The accumulaters are cast iron. They are removable with the trans in car. They have their own gaskets. Low accumulater is on passenger side. There is no check ball in low acc. The gaskets can be cut yourself but they are a bit complex, I would reccomend using a commercial gasket. The high accumulater is not your problem......Bob

[downunder pat]

Thanks to all who replied to my question.I am not machanical enough to try to fix myself(will give lesser jobs a good go) but all the given information will help tremendiously.29 TOURER KEN Irene look picture perfect and i do know how long it can take to get a nice car, as i imagine most people in the club do !enjoy.""

Patrick Maiden Buick Club Austraila nsw #991

jmaiden@iprimus .com.au

[autotran]

I am in the US and I sell all of these parts that have been mentioned in this discussion. I have been selling Antique automatic transmission parts for over 30 years now and I ship regularly to Australia and anyplace else in the world. Dave Edwards BCA #8371

http://www.autotran.us/dfkits1.html

http://www.autotran.us/dfparts1.html

[Bhigdog]

I buy my tranny parts from Dave and can vouch for him........Bob

[downunder pat]

Thanks Dave i will be ordering parts through you .(when funds permit and i can find tranny man suitable to see whitch parts are needed))Could i ask you question if thats possible Dave as per my first posting (dynaflow blew low still workes in drive and reverse).Do dynaflows like steep inclines? I like the way dynaflows drive but my driveway is short but has fair incline.And are there any tricks ect to putting these things together? I do realize as well as beeing a club member you are running a busisness and as all of us time is is allways in short supply but if you had time to answer these ones i would be greatfull

regards Patrick Maiden bc/au #991 Nsw