63 Riviera Dynaflow Transmission Swap

I own a 1963 Riviera. I bought it about two years ago and I am very happy with the car. My only problem has been a slow leak from the Dynaflow transmission. I met with the owner of a very reputable transmission shop who specializes in classic cars and he said the minimum cost to look at the cause of the leak would be $2000. He said that he would recommend a rebuild since he was going to drop the tranny from the car.

I have met with a '64 Riviera owner who lives close by. He has a Turbo 400 in his Riveria and is looking to upgrade. He is willing to sell me his tranny for $600. He said that he read an article online which stated this swap was possible but that there was a small lever on the crank which needed to be removed. Removing this lever would require balancing the crank afterward. This seems like a lot of trouble.

I rode in his '64 Riviera and noticed a big difference in acceleration with the Turbo 400 tranny. As you know the Dynaflow is a smoother but slower launch.

I would like some advice on this matter or possibly other alternatives.

Gary

Gary,

That is a very typical transmission shop answer. They shoot you a high price for two reasons, either they don't want the work and hope you'll go someplace else or they want to make darn sure they are going to make some real money on the job. They also feel that if they fix a leak and something else starts to leak at a later date, they'll get blamed for it, so the complete rebuild is the only service they will perform. Many times the leak is caused by something simple like a pan gasket or a output shaft seal, both of which can be serviced with the transmission still in the vehicle. The Dynaflow is not a complex transmission and actually has fewer seals, clutches and bands than the THM 400 that you are thinking of swapping. If I were to go to the trouble of swapping out the Dynaflow in one of my 63's, I would look at the THM 700 as a way to get a modern transmission with overdrive. Lots of directions you can go here, you have to decide what fits your needs and pocketbook!

Good Luck!

Tim McCluskey

Gary,

I have a 63 with dynaflow. it had a small leak when I bought it and from everything I have heard on these forums that is very common with that trans. I drove my car for two years with no change in the leak but eventually it got much worse. I had it rebuilt by Pete Phillips here in Texas, I found that all the transmission shops say they have experience with dynaflows but in reality they do not, you need to be careful. I have also heard that the conversion to the later turbo is quite involved since the crankshaft in the 63 is different from the 64 and later, other more expert folks here can give you better info I'm sure. I stuck with the dynaflow for originality but it all depends on your overall plan for your car.

I have a transmission shop in Houston that knows and loves these old transmissions. He has rebuilt 2 dydnaflows for me and can normally get them out in a couple of days.

Of course, you have to bring the transmission to him to do it.

While it was out, you may want to thing about the U joints / CV Joints and center bearing as after 40 + years, they probably could use some work.

Thanks for your quick responses. I would like to keep the Dynaflow but want the performance of a newer tranny. Also, there seems to be fewer transmission shops working on Dynaflows in my area(New Orleans if you haven't figured that out yet). I am looking at the long term for future maintenance issues and parts availability.

Tim63Riv - Where can I get a THM 400, what additional changes as far as...linkage requirements, possible drive shaft change, console shifter change...etc. do I need to look at? I don't mind spending a few bucks but within reason.

I would like to hear from somebody who has made a swap and reply with their experience...good or bad. I am open to "diehard" Dynaflow readers who can convince me to keep the tranny I have. My car is more of a weekend driver, not a show car.

Thanks again for your replys!

Gary

Gary,

I'm sure there will be many more posts to this thread concerining your trans swap. Here's my 2 cents worth on the swap. If you're going to swap in a TH400, opt out of the 64 in favor of a 65/66. The latter is the one that came with the switch pitch torque converter. It's no more work to do this swap than it is the one for the 64.

Good news/bad news: Good news - none. Bad news - Swapping a TH400 into a 63 is not a bolt it; you'll need to either put a later model crank in your 63 engine, or put an adapter hub on the crank you have. You'll need different transmission crossmemebers and transmission mounts, a different driveshaft, a different starter motor, a different flex plate, a different carburetor and linkage. You'll need the console and shifter from the same year car as the trans (a 65 console with shifter will work for a 66 trans.) 64 has D & L only, 65 has D, 2, & L. Parts of the different consoles are different lenghts to accompodate for the additional detent on the 65 shift quadrant. Then you'll need to find the wiring harness and switches to control the kick down and switch pitch solenoids. If you'd like I can go into more detail about "why" for each item I've mentioned.

Personally if you're looking for something "more modern" go with what was mentioned in one of the previous threads and go with either a 700R4 or a 200R4. As long as you're having to re-do everything, you might as well go for a real improvement.

If you're not racing your car, and you've not done anything to the engine to improve performance, there would be no real reason to go for the later trans. The dynaflow will run forever if you can control the leaks. It's totally fluid driven with no real hard engagement parts. Shoot, you can even push-start a Buick with a dynaflow if your battery dies. Find someone who will fix your leaks and learn to love your dynaflow. My 63 has 197,000 miles on it now. A quart of trans fluid every once in a while is not nearly as expensive as a rebuild when you just have a leakage problem.

I've done quite a bit of research on a nailhead/200R4 swap for my 64 Riviera. I'll be glad to share with you what I have so far.

One much cheaper thing you could do to improve "off the line" acceleration would be to put in a higher numerical gear ratio in the rear end.

Ed

I agree with RivNut and keep the Dynaflow. It's actually quite nice to drive the car with it and who needs quicker acceleration when the car was designed to be the ultimate cruiser. Realize and enjoy that aspect of it and you'll soon forget about swapping it out. I mean if you want to tear into the engine and go through all that just to get off the line quicker, go buy something else and leave the Rivi alone. Trust me on that.

Ed & Jim,

Thanks for your good advice. I think I will stay with the Dynaflow and keep the car close to its original specs. I don't want to start a major rebuild of the engine, drive shaft...etc. just to get a little more acceleration and less fluid on my garage floor.

Regarding the leak, what should I look at first before going to a transmission shop? From what I can tell, it looks like it is leaking from the front of the tranny. The gaskets are all cork (the previous owner stated this). I drive the car weekly so the gaskets should be well lubricated.

Any comments or advice would be greatly appreciated.

Gary

I think you are making a good choice to keep the dynaflow. Take the cover off the torque converter and make sure all the bolts plus the drain plugs are secure. Gently tighten the oil pan bolts but not too tight. Biggest item in my case was not leaving the car sit too long, drive it as often as you can. You may also want to try a bottle of seal restorer.

Interesting. Not many TH400 transmissions will bolt up to the 401/425 without expensive ($700 and up) adapters. But the 64-66 Buick trans was sold by GM as a sort of universal trans and came in Wagoneers that had Buick V6 and V8 engines through '70. Apparently you may find one in some Jaguars and Rolls Royces as well. They'd just cast up an adapter bellhousing to go between block and trans case.

So far as I know the only requirement to use the TH400 is the correct flexplate.

Yup, that's what they all think, until you go to actually try to do it. Then you discover the crankshaft is not quite right and the balance is wrong and before you know it, you have a big job on your hands...

The TH400 required an adapter, but the forerunner of that The ST 400 was made specifically to fir the 364-425 bell housing. The problem was that the back of the crank was altered when they switched from the dynaflow. The only Buick engines that accepted the ST400 without any problem were the 64-66

If anyone wants to convert their early Riv to 4 wheel drive - heaven forbid- Jeep has already fabricated the transfer case to bolt to the back of the 64/66 ST400. Jeep continued to use the round bell housing TH400 case long after Buick had switched to the BOP corporate case; however, the internals of these transmission were not of the switch pitch variety, they were corporate GM TH400 pieces.

Pontiac59 (name unknown) explained how other car companies contiuned to use the older design and create adapters to bolt this trans to their existing blocks, but what he left out was how you converted the mechanical kickdown linkage of the dynaflow to the electrical kickdown of the ST400. ST400 was Buick's name for the TH400, and how you go from a shifter quadrant of PNDLR to one of PRND2L.

Buick had been using the term "Turbine" when refering to their transmissions for a long time and wasn't about to make a name switch so they just renamed the "Turbo Hydro" as "Super Turbine." If you look up the same part for a Buick ST400, or a Olds or Pontica TH400, you will get the same part number.

Were these other companies trying to save a buck by using the Buick trans, OR was there nothing better?

Ed

Ed,

GM used the 400 with many of the Chevy and GMC 4X4's so you don't need to cross over into the enemy camp to get a transfer case that bolts to the 400!

Urban legend about the Jeep 400's! The case LOOKS somewhat similar, but it is not the same. The Nailheads have the starter on the driver's side, the Jeep on the passenger side. The bellhousing is somewhat abbreviated on the Nailhead version so the front of the torque converter sticks out past it, the Jeep bellhousing fully covers the torque converter. I usually direct folks over to ebay and have them search Turbo 400, there is almost always a nailhead 400 and a Jeep 400 up for auction. Once you have seen both, you'll understand about the differences!

Speaking of a four wheel drive Riviera, there was a guy out west of the Twin Cities trying to sell a 63 that he had attempted to put on a Blazer(?) chassis and never got done. Saw the car on Craigslist for about $500. A month or so ago I was at French Lake Auto Parts and there was the car. It was a low option, rusty Minnesota car, but it had a right hand remote mirror on it which I now own! Occasionally even I get lucky!

Take Care,

Tim

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: RivNut</div><div class="ubbcode-body">Gary,

I've done quite a bit of research on a nailhead/200R4 swap for my 64 Riviera. I'll be glad to share with you what I have so far.

Ed </div></div>

please send me info on this

thanks,

wes bilgerat671@juno.com

Reading this one with great interest. I'm modifying a '54 Roadmaster in great need at the moment. I see where a lot of this post may not apply to me, but my plan was to upgrade to a 401 and mount it too a T400 that I recently picked up. I was under the impression that I would only need a crank adapter (which I have), flexplate and starter to get this trans connected to a pre-'64 motor. Aside from the issues of getting the whole thing connected to a rear end, etc., are there engine balancing issues that will come into play?

Thanks!

Gary

Gary,

If you're putting an ST400 in a '54, you'll need to do more than just drop it in. The '54 has a torque tube rear end and the ST400 has an open drive line. When removing a torque tube and replacing it with an open driveline you're removing an intergal part of the locating mechanisms. You'll need a new rear end as well and you'll also need to fabricate upper and lower control arms to attach the rear end to the chassis.

Go with a 401/425 with an early 401 crankshaft (the stroke for a 401 and 425 are the same, the 425 had a .125" larger bore) and bolt a 59/60 dynaflow to it. Make a couple of small mods to the motor mounts and drop it in using the existing torque tube setup.

Ed

Ed; If you don't mind I'd like to take you up on your words from 6 years ago, see message #6 in this thread!

When doing a swap to a say, ST400/TH400, what needs to be changed and why? Just very curious what kind of a shopping list would it sum up to!

Others can of course add to the pile also.

Thanks.

Lasse

Oh boy, lets see what I can tell you about the differences between a '63 with the dynalfow and a '64 / '65. First of all the '64 ST400 is different than the '65/'66 ST400. The former is a one year only transmission but it's still basically a GM TH400 (ST was a Buick marketing name.) The '65/'66 has the variable pitch torque converter so except for the hook up of the variable pitch, the 64 - 66 is the same. But now back to the differences:

1) The crankshafts are different, they have different sized flanges on the rear

2) The flex plates are different. The '63 is triangular shaped, the 64/66 is round and they're not interchangeable because of the flange. Russ Martin sells a piece that you can insert into a '63 crank to mount a '64 - 66 flex plate.

3) The starter ring for a '63 is on the torque converter, the ring on a '64/66 is part of the flex plate. This means the starter motors are different, the nose on the '63 is longer.

4) The shift patterns are different. You'll need a different shifter assembly. That means the neutral safety switch and the back up light switch are in the wrong place and the detents in the shifter gate are different.

5) The transmissions are different length. So you'll need the drive shaft from the ST transmission. But you can't use the entire assembly. They 63 driveshaft connects to the rear pinion with a U-joint; the '64 connects with a flange. You'll also need to drill the frame and use the 64 - 65 transmission cross member.

6) The St transmissions have the kick down / switch pitch mechanism connected to the carburetor so you would want the carburetor that goes with the transmission 64 for 64, 65 for 65, and 66 for 66. If you go with the switch pitch transmission, you'll need a switch on the brake pedal arm to activate the high stall when the car is at a stop.

If I were going to do this, I would find a '64 or '65 donor car and do a swap of the entire running gear. That way you would have everything you need to make the swap.

Unless you have a really specific reason for wanting to do this; stick with the Dynaflow.

As I think of more, I'll update this thread.

Ed

Hi guys,

Coming back to this topic: Moving slowly but surely, I am a bit closer to getting the transmission swap done. I bought the converter piece by Russ Martin (found it second hand in Finland) and now I would be happy to get some additional advice: Can someone point me to a respectable/dependable transmission shop, who could sell me a re-built 700R4 or 200R4 tranny? I have a quite good setup on the shipping over to Finland, but as you can understand, the before mentioned qualities are essential for me because I can´t just stride over and look the shop owner in the eyes. And by the way, which one should I prefer (I know this can be an eternal question) and is there big variations within for example 700R4:s?

Also vendors for the other stuff needed in the swap would be highly appreciated!

Thanks!

Lasse

Look for a transmission from a reputable builder like Art Carr or someone of equal status. Buy one that has been upgraded to handle the torque of your engine - remember, these transmissions were originally behind small V8's and V6's.

You HAVE to incorporate a TV (throttle valve) cable. If not, you'll burn up a new transmission after driving it 50 meters - not kilometers but meters.

The 700-R4 is physically larger and makes fitting in the X frame a really close call. It also has a really deep first gear compared to the 200-4R 3.06 vs. 2.74. The 20-4R has basically the same gear spacing as the ST400 with the addtion of the overdrive. The 700-4R has a .70 overdrive, vs. the 200-4R's .67 overdrive.

You'll need to rework the detents on your shifter for the 4 forward speeds.

Old Post. New Member.  Love the performance and smoothness of my 63 Dynaflow.  If being able to smoke the R rear tire all the way thru low even at 5000 ft. isn't enough what is?

I have a friend who drives a semi-custom 63.  He makes money betting on how long he can smoke the RR tire at swap meets and car shows.  So far he’s way ahead $$$ wise.

Until something breaks, then he'll be behind

2 hours ago, telriv said:

Until something breaks, then he'll be behind

People keep telling him that but ………

He’ll learn the hard way.

On 3/22/2022 at 12:37 PM, Thomasso said:

Old Post. New Member.  Love the performance and smoothness of my 63 Dynaflow.

On this topic, with this post started back in 2007, haven't seen much on swaps specifically for TH400. Lots of posts on OD transmissions.

Too many things to address before I get to do an actual ST-400 swap. Funny thing, my inefficient Dynaflow with the missing/stripped nut on the torque converter leaks a mere drop or two and functions perfectly!

My BJ-65 switch-pitch core awaiting for 42+ years in storage for a rebuild!

Nothing like a spare Dynaflow to use as a base for a little winter work out with resistance bands. I bought it for $40 around 1985 when the local junkyard tore down "the tin building" just in case I needed spare parts.