Next task with my 64 DeVille project is to check TH400 condition. Gearbox came with the car but was already removed. It is 64 but not possible to say if it is the original to this car as there is no VIN stamped like in later gearboxes. And again we have one-year-only part, so I hope no need to replace mechanical parts. I got 64 gasket kit already but probably will need some more rubber for inside parts.

Two bolts from extension housing were so corroded that they broke when opening, otherwise no damages yet. O-ring in filter was not properly in place, and was cut actually. Modulator is not holding vacuum so need to be replaced. Governor valve is stuck, I hope cleaning will solve that.

I will clean all parts and replace gaskets, and other parts if necessary. Oil was very clean and red inside but I think oil has been changed or added not long time ago. 
 I can see that 64 is slightly different from 79 which I repaired year ago. All hints and advice are highly appreciated. Shop Manual is in heavy use.

Views: 632

Reply to This

Replies to This Discussion


Are you sure you didn’t work for AMCO transmission in a prior life  ? ?


That's AAMCO beep beep. In case they don't exist in Finland, here you go:



The video says it all 


Thanks Tony

Local transmission shop asked 2500 USD to fix the TH400 in my Seville so I thought I will first try myself and pay that huge amount only as a last chance. So far I have kept the money in my pocket.


If at all possible depending on the timing of your  turbo  trans restoration would it be possible to show a picture of the Governor — valve body and forward clutch assembly  you rebuilt 

Thanks in advance for this very useful info 


Hi Tony

I made short video to see how the piston has to move freely up and down inside governor.


Thank you very much for a look at that governor 

Btw where did you get the trans mount?

TA Motor on Sweden. (I live in Finland).

They were available in Rockauto some months ago with very good peice but not anymore.


Like  to let you know that Kim’s repair of his rear main engine  crankshaft seal is holding up with no sign of any oil leaking for the first time I can recall ( been years on this site ) 

For the short term  looks like we finally got that repair squared away for good 

Your engine rebuild  timing is spot on to take advantage of that once in a long time repair that is finally working as it should be 

Just remember —-that getting these cars out and about is the real joy and excitement of owning them — so you have a lot to be looking forward to in the not so distant future 


During rebuilding my 64 TH400 I found out some technical features which are related to our year 1964 or a bit later, but are different to TH400 from later years. Good to check these if you are repairing your gearbox or sourcing parts for it. Most of this is defined in Shop manual when you read it very carefully. I am far from specialist regarding transmission so please correct and add data where needed.

First of all, the main case is one-year only for 1964. Probably similar case can be found in 1964 Buicks. Case is installed to 429 with adapter ring which is not needed in later models. So please handle your 1964 TH400 with extra care because it might be not so easy to find a replacement!

The control valve assembly is 1964 one-year only. It means that the spacer plate and spacer gaskets must be 1964 model. One of the fixing screws has copper washer which is not used in 70’s and later.

Oil pump is 8 bolt version which is regarded the strongest and the best. I believe it is possible to use 6 bolt version from later years as well if 8 bolt version not available.

Inside the case 1964-1966 TH400s have a sprag assembly instead of a roller clutch assembly. Sprag is regarded stronger and recommended when building hi-power modifications.

The extension bushing has 1.8” outer diameter whereas 68 onwards has 2.0” diameter. Extension housing seal is smaller as well, it has 2.502” outer diameter in 1964-67.

1964 TH400 has a center support locating screw which is not used in 70s and later. It helps to position the center support before tightening the center support bolt.

1964 TH400 has 5 pcs of 0.068 wawed metal plates in Forward clutch whereas later models have only 1 wawed plate. Thanks to this 1964 has extra smooth engagement of gears! I was lucky to find a NOS kit.

Oil filter in 64-67 is different from more common flat type filter used since 1967. In our filter the o-ring is installed to filter neck before installling the filter to gearbox.


That is the most detailed  64 TH- 400 transmission  rebuild info that has been posted to this site since 2006 and the other websites that this site has evolved from years ago 

This will be of  very great help  for years to those who have the skills to  be attempting to rebuild there 64 trans 

Sometimes it is just this kind of info one needs to say - Hey  I can do this myself !! 

I think most have to keep this task to the  trans pros which would include myself but enjoy knowing the details anyway 

I am extremely happy to learn —-that the 64 trans is built with  stronger parts that are known to be the most durable TH-400 trans built compared to some newer years that followed 
Knowing that I have one of the better built. tH-400 trans is a very nice thing to be finding out 

Nice Work Matti and thanks for sharing what you discovered 




  • Add Photos
  • View All


Suspension on 63 cdv

Started by Kim K Kaiser in 1963/64 Cadillac Specific Discussion. Last reply by Tony and Ginny 429 3 hours ago. 2 Replies

Hi all.   my 63 has developed squeaks and creaks recently.   I took a look at the ball joints and associated rubber parts, and they do look a bit worn.  I have replaced shocks in last year or so.…Continue

KleerView/OptiKleen Bottle Location

Started by Logan Robb in 1963/64 Cadillac Specific Discussion. Last reply by Logan Robb 21 hours ago. 3 Replies

I just received a repop KleerView bottle and label for my 64 Fleetwood this morning. Wondering where the best location for this bottle would be? Or rather, where was it most commonly installed?I…Continue

Current 1963/64 Cadillac Listings on eBay

Started by Jason Edge in 1963/64 Cadillac Specific Discussion. Last reply by Jason Edge yesterday. 1 Reply

To see all 1963/64 Cadillacs Listed on eBay in the USA…Continue

Tags: ebay

1964 A/C Delco Parts book for Deville

Started by Mark Bartlett in General Discussion. Last reply by Jason Edge on Tuesday. 1 Reply

Is there a place to go to buy or look at original parts book ThanksssContinue

Blog Posts

Lower Front End Ball Joints

Posted by Logan Robb on May 11, 2023 at 9:04am 7 Comments

Good Morning all! 

I took the 64 into the shop to have some adjustments completed and in the process decided to have the lower ball joints replaced as was recommended the last time I had it in. I ordered the parts and came into the shop. They quoted me nearly $500 to replace those lower ball joints requiring nearly 4hrs of labor. Now this is a reputable shop and they know me by name here and they will continue to get my business. I am just questioning what on earth is…


1964 power steering sector rebuild

Posted by CHRIS CARLSON on March 20, 2023 at 11:32pm 3 Comments

 I'm having my steering sector rebuilt, and considering changing it from 20-1 ratio 4.2 turns lock to lock to 3.5 turns lock to lock @ 16-1 ratio, If i change from a 3 1/4" box to a 3" box i could have a 14-1 Ratio steering response would be faster, shorter distance to turn the wheel to get a response,   has anyone done this? and how do you like it? thank you

1964 Daville dashboard clock

Posted by Willem Bol on March 13, 2023 at 11:33am 2 Comments


Can somebody help me finding a dashboard clock  for my 1964 Cadillac DeVille Convertible?

Thank you in advance,

Willem Bol

The Netherlands

Does anyone know where I can get the bushings for AC compressor mount on the 429?

Posted by Robert Schles on February 21, 2023 at 11:45am 2 Comments

I've looked at the usual rubber sources but couldn't find any. 



  • Add Videos
  • View All

© 2023   Created by Jason Edge.   Powered by

Badges  |  Report an Issue  |  Terms of Service