dynaflow transmission

[john compono]

does anyone know if you can swap out a 55 Buick dynaflow for a 56 dynaflow ? having some issues with mine and I found a 56 Buick dynaflow never installed in Michigan. the guy tells me this 56 will work in my 55. does anyone know for sure before I take a chance to get it ?  mine is a 55 century and the tranny he has is for a 56 special. he said it will work.

[NC-car-guy]

12 minutes ago, john compono said:

does anyone know if you can swap out a 55 Buick dynaflow for a 56 dynaflow ? having some issues with mine and I found a 56 Buick dynaflow never installed in Michigan. the guy tells me this 56 will work in my 55. does anyone know for sure before I take a chance to get it ?  mine is a 55 century and the tranny he has is for a 56 special. he said it will work.

It is not exactly bolt in.  You'll need the rear end from the 56 as well.  They had a different driveshaft, which means the trans has a different tail shaft.   There are plenty of 55 dynaflows around where people have swapped for modern transmissions.  @MrEarl might have one or two down in Georgia.

[john compono]

mr earl the gentleman said that from 53-56 the trannies were the same and that he has swapped out a 55 tranny for a 56 and the car ran great and he never changed the rear end. now I'm getting confused. maybe find the same tranny for my 55 century but thanks for your input. appreciate it.

[john compono]

sorry meant to send that last message to you NC-CAR-GUY 

[NC-car-guy]

12 minutes ago, john compono said:

mr earl the gentleman said that from 53-56 the trannies were the same and that he has swapped out a 55 tranny for a 56 and the car ran great and he never changed the rear end. now I'm getting confused. maybe find the same tranny for my 55 century but thanks for your input. appreciate it.

Here's a couple links:

 

 

[john compono]

if anyone out there needs any parts for a 55 Buick 2 door hardtop century model let me know. I have some very nice and clean extra parts that I want to sell. contact me and I can let you know what I have. just a few things off top of my head that I have is, 4 original powder coated Buick rims that look brand new, have some nice moldings, front bumper and some parts etc... 

[KNUT]

If a 56 Dynaflow is to be installed in a 55 Buick you should know the following. The overall length of the 56 transmission is 1 inch longer than the 55 small series transmission, but have the same overall length as the 55 big series transmission. The  56 converter and bell housing is 1 inch longer than the 55 converter. This means that the oil pan also is shifted 1 inch rearward. So you need to use the 56 pan. The 56 universal joint has finer splines than the 55, so you need to use the 55 u-joint and torque ball. You also need to use a 56 cross member supporting the transmission since the extension housing also is shifted 1 inch rearward. If you buy the 56 transmission, I think it will be easier to replace the bell housing and converter and install your 55 bell housing and converter if good. Also, you still need to use your 55 u-joint and torque ball. I hope this was helpful.

[john compono]

thank you very much Knut for the information. now I understand what has to be done. by not doing the changes you mentioned would this cause the rear main seal to leak ? 

[2carb40]

I have a 1955 Cent 2dr ht. It currently has a 1956 dynaflow transmission in it that I installed. The 1956 Dynaflow is 1" longer than the 1955Spec&Cent

You can install the 56 dyna in a 1955 Super or Roadmaster much easier becuz those transmissions were equiped with a longer tailshaft. I took care of the extra length proble by studying the different torque balls used in that era. I used the 1948-52 torque ball which is shorter than the 55 Sp/Cent. I noticed my 55trans cross member was 'offset', I also had a 1955

Standard trans crossmeber which is straight, but still needed to have the bolt holes slightly modified. When I brought the torque tube and put the splined end in the U-joint it stopped with an approx 3/8" gap. Since ai had installed a shorter toque ball the splined front of the driveshaft was too long and ran into the center of U-joint yoke, so I pulled the driveshaft back out and shortened a bit more than 3/8" and chamfered the end as original. The trans fluid cooler on 55s is mounted at the back of trans. The 56 has cooling lines running to the radiator. I bought a remote cooler and installed in front of radiator. The reason the 56 is longer is Buick added another stator and needed more room in the bellhousing. It performs better at takeoff cuz they changed the ratio affecting acceleration. The fine splines in the U-joint evidently had quite a few failures, some being twisted like a piece of licorice, probably from more stress on the joint from increased HP and the torque multiplication with the changes in the convertor. Just a SWAG((scientific wild ass guess)! Good luck! I consider it an upgrade until it proves itself otherwise.

[KNUT]

Hi John, 

I am not sure what you meant regarding the rear seal, but they are the same on 55 and 56. The seal is to be installed in front of the torque tube (not in the torque ball). Please let me know what the problem is with your 55 transmission. Further,  if you have a power window mechanism for the driver side door, I would be interested (I have the motor).

[KNUT]

2carb40. 
I read your post with interest. You could have used your original 55 oil cooler and pipes if you replaced the two brass fittings with the original 55 brass fittings. You would also need to use the original 55 heavy gauge angular thrust plate since the 56 thrust plate omitted the two threaded bolt holes for fixing the oil cooler. I think to use a 48-52 torque ball and to cut the front tip of the propeller shaft sounds a little scary, but perhaps it works…

[john compono]

thank you for the info 2carb40 and glad to hear someone also made a switch with the trannys. going tomato the switch also. heard nothing but good things about the 56 tranny. I'll keep you posted on how it works out.

[john compono]

hi knut I thought by switching the trannys it might of had something to do with the rear main seal dripping. I changed seals twice so far and going to try a third time. old tank sent me a way to do it and sez he never had a problem again with his. so I'm going to give it a shot. reason why I'm switching transmissions because out where I am there is nobody with enough experience to rebuild mine so I took it out already and hoping to install this 56 I got with my cousin here in New York. trying to find guys that know how to rebuild these transmissions are a dying breed unfortunately and if you do they bang you over the head with the cost and there's no guarantee it will be done right. not going to take that chance. as far as that part you need the power window mechanism that I don't have. my 55 has no power anything. you might want to try the GTO GURU IN OKLAHOMA. he seems to have everything like that for buicks.

[2carb40]

IMHO, losing 3/8" off 5-6" long of splines, Ill take that bet. Lemme know if you need parts. Or if you get really daring and want a complete stick changeover. I have a few parts in my 30X40 storage bldg.

[Bussa]

Tell us about the black car on the hoist !   '65 Special ??

[MrEarl]

 

[KNUT]

Ok John. If you only have a leakage problem in the rear end, and the 55 transmission otherwise works, that should be easy to repair. The seal in front face of torque tube is to prevent oil from seeping into the torque tube which finally migrate into the rear axle and further out into the brake drums. Check level in differential housing. This is an internal leakage. If you have an external leakage at the torque ball, you need to check the outer retainer. The original outer retainer has direct metal to metal contact with the torque ball and will create leakage over time. The newer outer retainers have a vulcanized rubber ring which thrusts against the torque ball and forms an outer seal. Much better solution. Check what you have, and let me know. 

[KNUT]

MrEarl. Yes, correct what you says. The difference in length is 1 inch. The 53 V-8 transmission, the 54 and 55 series 50-70 and the 56 transmissions have the same overall length. However, it is to be noted that the 53 extension housing is very different from the 54 and 55 and uses the same rubber mount as the manual transmissions. The 54 transmission would fit on motor, torque tube and the mounts, but you loose the “kick down” function and the internal “clicks” in different gear positions. In 54 they are on the steering column, in 55 inside extension housing (a new feature they used all the way up to 63).

[KNUT]

Further John. You said New York. You have real specialists on old time transmissions in NJ. Company is Fatsco transmission parts in Pine Brook, NJ. Ask for Larry or Mike. 

[john compono]

thank you Knut for the information and the tranny company in New Jersey. never heard of them but I'll give them a shout. thanks again I appreciate it. also its not the rear end that was leaking its the rear main oil seal. going to try another rope seal in it today. 

[Leif Holmberg]

[KNUT]

Hi again John. Could you possibly have a 55 seat side panel driver side for sale?

[john compono]

sorry knut most of the stuff I have is exterior like a nice front bumper with the dagmars, have some nice side front fender spears, a horn ring, have a working sonomatic radio, and some other side moldings and some stuff I haven't got to yet but I will let you know exactly what I have then.