So I havent seen this before but if its been posted please post a link Just thinking outloud about an overdrive for a Chevy torque tube overdrive. How difficult would it be to put a Saginaw 3 speed OD from say a 55 Chevy into an early Chevy Passenger car torque tube. I know it would involve an adapter of some sort, probably shortening the mainshaft. Has anyone done it? thoughts on this?
The Saginaw was later. Later 60s full sync. The Muncie was in the tri 5s Or that’s how it seems anyway The OD units are Borg Warner pieces. Lots of interchange between the units themselves. There were torque tube ODs. Possible to use some of those pieces Or go open drive
Here are some facts from my personal ownership of three generations of GM transmissions, 1) Muncie 319, 1950's through mid sixties overdrive, 2) 1969 Saginaw Borg/Warner 3sp+od, 3) 1985 General Motors T-5. I lined them up for a picture and they were the same length, all are a couple inches longer than a closed driveshaft Muncie. So, being that you wanted to mate a Saginaw overdrive version to a torque tube you would have to cut and respline the torque tube or cut and reweld to fit the longer transmission. Additional machining for an adapter interface of the conventional transmission to the torque tube. Conclusion for me was to drop a 3.90 differential into my axle housing and go the driveshaft route. Much easier, although I've got to believe that the objective would be well within the wheelhouse of a competent machinist. Post script I coincidently was looking at my records today and 12 years ago I had a mishap with my 1962 Muncie 319. I seem to recall my wet foot slipped hard off the clutch or at any rate I limped her home with a bad sounding and acting 2nd gear, dropped the transmission and over a 4 day period readied my 1969 Saginaw Borg/Warner 3sp+od and dropped it in with no change to the driveshaft. I knew they (the transmissions) were the same length.
Enough of the same idea has been performed on Model As over the years. I saw an A torque tube at Hershey with a '55-'65 Chevy overdrive grafted to it.
trying to figure out this statement. Are you saying that there is an open drive center section that fits in an early chev torque tube rear axle? if so what did you do about the rear axle pivots where it meets the leaf springs?
Yes, this is a truck application, I should have stated that. My Chevrolet truck 1949 rear axle housing had an original 4.10 closed driveshaft. I had heard about but I have never actually seen a Chevrolet closed driveshaft overdrive either for a car or truck. In 1997 I met Jack Halton, past president of Inliner's.org at the Eastern Regional Inliner's get-together at the dirt track facility and grounds at The Latimore Valley Raceway in southeast central Pennsylvania. Jack drove up from Florida in his '51 GMC with a 302 GMC, Muncie 319, and a GMC/Chevrolet 3.90 rear from a '55-'62 truck. He gave me the formula. Burn off the articulating rear mounts, lose the torque tube and center section, acquire the 3.90 rear. Using the original housing and axles the 'new 3.90' fits perfectly. Using my original springs I was instructed to purchase a rear axle mount kit from Buffalo Engineering out on the left coast, which is welded conventionally and found an open driveshaft to fit. I ended up buying one of Jack's Muncie 319's and drove that set up for 75k. I've since replaced that with the Saginaw Borg/Warner 3sp+od and rebuilt and sold the Muncie 319 to a friend.
So I had noticed with interest that the later open drive ten bolt center sections/drop outs seemed to have the same flange and bolt pattern as my 32 passenger car rear which has a closed drive. I may be looking for an open drive conversion in the future. Any knowledge as to how early these similarities go (axle compatibility and housing?). I dont want to swap out my housing as I intend to maintain the original mechanical brakes. (Vintage hot rod/speedster build).
Well, the torque tube has been used in the Corvettes with great success, and they were stronger than an open driveshaft in the day. The problem is the way the ring/pinion is setup. I'm going the other way on mine. I have a torque tube but replacing my rear end with a '55 read end with open driveshaft. There are a lot more options on the open driveshaft, and a 3.38 ring/pinion was avaialble in '55. OTOH, do you want to buy a torque tube rear end and torque tube? PS - Cosmo49 good to see your name!
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