Yes a U joint. So is the drive shaft from a 3 speed setup different than a rig that had a 4 speed? Or is the problem adapting a 3/4t tranny in a 1/2t truck?
The drive-shafts might be different and there might be a problem adapting a 3/4 ton transmission to a 1/2 ton truck.
Depends on the years.
- None, one or the other, or both might have had enclosed driveshaft fitting at the rear of the transmission.
- One or the other driveshaft might have been a closed driveshaft, or have an open driveshaft or have a short enclosed extension "shaft" behind the transmission.
The most useful way to get an answer/suggestion/opinion is to identify (in words or photos) the transmission types, the fitting at the rear of the transmission and the type of drive shaft end that goes/went into the transmission (as I think that Jason has done).
If Jason is referring to:
- an original 3-speed transmission from a 1950 1/2 ton Chevrolet truck, that would have been an enclosed driveshaft.
- an original 4-speed transmission from a 1950 3/4 ton Chevrolet truck, that would have been an SM420 4-speed transmission that was set up for an enclosed driveshaft.
In this case, the appropriate u-joint assembly would be: a front yoke for an enclosed SM420 4-speed and a rear yoke for an enclosed driveshaft 1/2 ton rear-end.
In this case, maybe someone will post information on yokes, joint, and bushings/trunnion-bearings (if needed - I forget what they look like) that would work in this application.
Or, post a want-ad in the Swap Meet (I got a set from Bruce Bugay and from WD Foster); or, call Jim Carter (he might have a used or rebuilt assembly).
