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Selliott

1955 century interchange question.....

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Hey guys I am new to the forum and just picked up a 1955 Century 4 door hard top. The nailhead is running good, but the transmission is missing so here is my question...... I have located a 56 dynaflow that was attached to a nailhead. Will it swap? I was told there may be a difference in the ATF cooling? Just wondering if it will work, I can get the 56 tranny for a good price.

Thanks,

Shon Elliott

Lubbock, Texas

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The cooling is an easy fix, but the length are different between 1955 and 1956,in 1955 there was 2 different length "Special and Century"same length,and Super and Roadmaster same length,non of them has same total length as 1956. 1956 are the first year with the same total length on Dynaflow and can be changed between the different models.

The bult pattern are the same if you can figure out how to fix the length.

Leif in Sweden.

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Hello Shon, I have a 55 Special, trans failed, installed one from my parts car (55 Century), was 1 inch longer but I modified rear mounting by slotting some holes, moved the differential back 1 inch and bolted all down. Worked fine. Later after doing alot of research, I found out that it must have been a 56 trans because it has an aluminum bell housing which is also 1 inch deeper to front of trans. Someone may have swapped over the high accumulator in put it in the Century. Soooo... it probably will work but is not correct and tires will be a little out of center in rear wheel wells. Do a search in the forums and you may find several threads that will help. Does the 56 trans you found have the same hi accumulator on the drivers side with a linkage arm toward the frame? Did you measure the total length on both? Mine may be a hybrid that was modified to work in the Century, but it does have aluminum bell housing. Interested to hear what you find out. Good luck, TexasJohn55 PS I don't know any history on either of my cars. Apr 13, A NOTE FOR CLARIFICATION: THE HIGH ACCUMULATOR FOR THE 55 AND 56 SHOW TO BE THE SAME PN IN MY GM DYNAFLOW PARTS BOOK, High accumulator PN 1391940 and is unique to the 55 and 56 trans. 57 used a different number. TexasJohn55

Edited by TexasJohn55
Clarification (see edit history)

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Shon, There are no "absolutes" on 60 year old cars. Don't take any information for granted as correct unless you find it confirmed somewhere. Some assumptions to veracity may lead you down the wrong path. Old saying about "assume" is true, it is actually three words that will make an "ass" out of "u" and "me". John

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Shon, There are no "absolutes" on 60 year old cars. Don't take any information for granted as correct unless you find it confirmed somewhere. Some assumptions to veracity may lead you down the wrong path. Old saying about "assume" is true, it is actually three words that will make an "ass" out of "u" and "me". John

Thanks for the advice..... I bet I will have lots of opinions on every question I ask.....

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According to the Hollanders interchange book, for identical transmission units a Dynaflow from a 1955 Special or Century interchanges or any 1956 Dynaflow will interchange if you include the U-joint. Here is a good thread to read, it also shows the '55 Special/Century used the same Dynaflow:

http://forums.aaca.org/f162/dynaflow-code-letters-1953-59-a-328330.html

Edited by sean1997 (see edit history)

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...or any 1956 Dynaflow will interchange if you include the U-joint.

only in the big series 50-70

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only in the big series 50-70

so JUST for clarification Willy, what you're saying is the length of the 56 Dynaflow matches the length of the 54 and 55 big series Dynaflow's but would be too long for the small series 54/55?

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so JUST for clarification Willy, what you're saying is the length of the 56 Dynaflow matches the length of the 54 and 55 big series Dynaflow's but would be too long for the small series 54/55?

yes

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