1957 Buick special transmission upgrade

[Frank Falconeri]

My 57 Buick has the 364 nail head rebuilt with the dynaflow  and torque tube set up, I was wondering if anybody out there has swapped out the dynaflow with a more modern 700 R4 and how difficult ultimately swap out is this going to be hard like selector on the steering column and so on and so forth do I need to rearrange and suspension components, Would love to know what's involved and do I have to remortage my house in order to do this. Anyone done this, also thinking of 4 way airbags as well. Any thoughts welcome. Thanks 

[Larry Schramm]

Usually simpler and cheaper to fix it back to original.  Plus you get the value of driving the car/vehicle as it was new.  

Also usually easier to fix if it is original and you need to get a particular part.

[EmTee]

The elephant in the room is the torque tube drive.  Going to any modern transmission (even the ST-400 from a Nailhead) will require converting to an open driveline and the associated rear suspension modifications.  So, if you go that way you might as well consider 'bagging' it 'while you're in there'...

[Bloo]

18 minutes ago, Frank Falconeri said:

Would love to know what's involved and do I have to remortage my house in order to do this.

Most likely yes. Any driveline/drivetrain modifications in torque tube cars tend to be ridiculously expensive up front, with additional hidden costs at the end. Not for the faint of heart (or wallet).

 

20 minutes ago, Frank Falconeri said:

Anyone done this,

Yes, quite a few have done similar things if not exactly this. Look around in the Buick-Modified section on this forum. I believe I have even seen a 57, but I can't swear to it.

 

You would need to decide if you are getting rid of the torque tube or not. If you get rid of it and go to an open driveline, you don't have a rear suspension anymore because apart from a panhard rod the torque tube *is* the rear suspension. Such conversions on Buicks are usually done using a "truck arm" suspension from a 63-72(ish) Chevrolet 1/2 ton pickup, and adding a crossmember to the frame to support it. A different rear axle would most likely be used, although using parts like the third member from a 61 or later Buick in the original axle housing might be a possibility. The Chevrolet "truck arm" suspension most closely duplicates the geometry of the torque tube.

 

If you don't get rid of the torque tube, you would need to shorten it, and have a Buick torque ball grafted onto the back of the 700R4. That would probably mean finding a 4 wheel drive (flanged) version of the 700R4. I don't know offhand if that exists, but it probably does. You would then need to have a machinist make the parts to get a Buick torque ball attached to that. At least that is probably how it would go, as I have never seen a kit to do that.

 

Either way, the 700R4 is going to be longer, and that will affect u-joint angle. On most Buick torque tubes, there is only one joint. In that case it is in the torque ball, and must run straight. Since it has to run straight, it cant have needle bearings, and must run bathed in oil. Some later Buck torque tubes have 2 u-joints, one in the torque ball and one at the rear. I think this is what you have. In this case, it follows the same rules as an open driveline, and the two angles must be the same.

 

Since the 700R4 is longer, the front u-joint angle will get tighter, and the rear will not because it is inside a torque tube. The angle that the engine and transmission are mounted will have to change, relative to the car. That can be mostly achieved by mounting the tail of the 700R4 a different height than the Dynaflow was. This might or might not cause clearance issues at the distributor/firewall, fan/radiator, and exhaust. You might or might not have to rework the front engine mounts. At the bare minimum, the first bend in the exhaust pipes is going to be wrong even if nothing else hits.

 

The shifter would need work too, yes, because the Dynaflow shift quadrant is different. I expect it is the easiest part of the whole deal, even tough I think you will need to have some parts machined. There are probably other things I haven't thought of. I'm with @Larry Schramm. Keep it as built.

 

Welcome to the forum!

 

 

 

 

 

[Frank Falconeri]

At this point I think I probably will just keep it going I see some axle fluid fluid on the garage floor looks like 90 weight I will have to put it on a lift and see if the rerend seal is leaking or if it's coming from the torque ball 

Edited November 7, 2022 by Frank Falconeri (see edit history)

[EmTee]

If the torque ball, it is likely ATF.  If the torque ball is leaking it may be allowing ATF into the differential, which may then be overfull and leaking.  Sharp looking Buick - I'd repair the leak and keep driving it!  Think any potential transmission/suspension modifications completely through and line-up everything you'll need before lighting the torch...