Ive had my cadillac for about half a year now ( its a 1956 sedan deville) and ever since i got it when the transmission warms up and tries to go in reverse it makes an awful banging sound and the car shakes. When the car is just started and probaly for the first 10 minuets it will go into reverse fine but after that it just makes the noise and moves backwards a litte bit. If i leave the car for about 20-30 minuets it will go in reverse fine. The no reverse makes driving and parking very annoying, i know people rebuild theses hydromatic transmissions but Ive heard its expensive and would have to be shipped out. On the hamb marketplace ive seen 56 engines and transmissions for sale would it be feasable to just swap the transmissions or is there any other avalable options. I dont have much experence with stuff like that but i know of a shop i can rent with a lift etc.
Can't help you decide, but the '56 Cad trans is a 1 year only nightmare, hard to find parts 40 years ago.
one option would be to adapt a newer GM th350/400 or 700r the adapters are available but not cheap but you have a more modern trans that is cheaper to build you will have to modify linkage and a driveshaft
I've thought about it but a newer transmission seems kinda wrong. any idea weather a 55 or 57 transmission would fit I have heard they are better
go with the 700r4 you have a nice cruising od that way. you have a one year only nightmare there nobody will know if you dont say nothing about the 700r4.
I have been selling automatic rbld kits and parts for 40 years now for 1946 to the mid 60's cars. I have sold many kits and parts for 1956/57 and up Cadillacs, Olds and Pontiacs. The biggest problem with the 56's is the "Front Unit Coupling Driven Torus". The shaft has/had 4 lugs which goes into the "Front Sprag Race", and it was inherently weak and tended to break. (A friend of mine bought a 56 Olds convt about 1959/60 and he had it one day when his broke). The reason I said has/had is because many were changed out during the late 50's and early 60's due to breakage. I don't know if GM ever had a recall because of this part. There were also a couple of other minor differences in the early 56 transmissions, and I have some of these parts if needed but most customers have never needed them. This might be because when the transmission failed due to the lugs these other parts were replaced at the time or it is a later 1956 transmission that never used these parts. The late 1956? and 1957 up transmissions had splines instead of lugs in the area and the problem went away. So in my opinion you should probably repair the transmission as it would be a lot easier than changing it to some other unit. Dave
The Jalopy Journal
