My crazy dynaflow swap idea

My55buick

Active Member
I couldnt sleep last night and when I was up all night I started to research ideas for my 55 Special. I tried to piece an idea together. I wanted to see what you guys thought. A big goal on my 55 is a semi stock appearance but make it a better driving car. I've figured out some of the simple stuff, now I'm working on the tougher stuff. The dynaflow in my car leaks and is just very slushy off the line, so I started thinking about that. I want to keep the stock suspension to maintain the nice buick ride, so swapping out the rear and control arms isn't something I like the idea of doing. I found a company that makes an adapter to bolt a Th350, 400, or 700r4 to a 53-56 nailhead. Then I found out the Corvette uses a torque tube and lots of people modify them. I found a few companies specializing in modifying torque tubes. This got me thinking, the tail shaft housing unbolts on most gm transmissions, so in theory couldn't I make an adapter that would bolt to the trans similar to the end of the factory dynaflow, and then the torque tube company could make me the custom shaft to go inbetween. Or is this just insanity?
 
I'm glad someone approves of my theory, so maybe it's not a totally crazy idea.

Here's the next question, because I don't totally understand it yet.... The torque tube works as the upper control arms and locates the rear end. I assume that puts pressure both up and down and left and right on the dynaflow as the suspension articulates. From what I've read the Dynaflow is cast iron, which makes it strong so it should be able to handle some stress. All the newer transmissions are made of cast aluminum which is nowhere near as strong. Would bolting a torque tube to a modern trans put too much pressure on the bellhousing and cause it to break off the transmission or at the very least crack?
 
trans crazy

My 55 Buick, I thought you said dynaflow was leaky & slushy? If this is true why would you change tail shaft assy . This would not make trans not slushy. Also I don't see any reason why you would want a torque tube. 1st. decide if your going to do a lot of highway driving if you are I would recommend a 700R4 with the adapter you spoke of and have a drive shaft made from trans to rear. If you are just going on short trips around town do the same but go with a 350. Just my opinion. Mikecad
 
See section 6 in your service manual, along with the dynaflow section to understand your drivetrain. Then get under the car and see how it all works.
Some additional explanations:

https://www.youtube.com/watch?v=hfo-afeabFA

https://en.wikipedia.org/wiki/Torque_tube

The Corvette tube is completely different and will not work....no other transmission will work with your torque tube.
What exactly is wrong with your transmission? The dynaflow is a durable transmission the either goes or it doesn't; it can be rebuilt.
 
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