VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 38 p.u differential swap

Hi Guys
I attempted to get the info on the stovebolt forum, perhaps I can get out of a dilema;
Presently I have a 1949/50 complete rearend under a 1938 1/2 ton pickup. After owning this for over 40 years I would like to restore it to running condition. Will the 1938 Sedan differential slip into a 37 pickup rearend?
I have a 37 pickup rearend and springs, 38 sedan rearend and springs, in addition to the 49/50 I run for about 20 years.
If the torque tube wasn't so long and the wheels lined up in the fender opening correctly giving an odd appearance it was satisfactory.
Any solid advice will be appreciated !!
Thanks, gene

The torque tube on a 1937 and 1938 truck is the same. The 1937-38 car torque tube is about an inch longer. The truck had a little larger differential also a different method of mounting the spring to the banjo housing. Wether or not the car T.T. will fit into the truck is beyond me.

Chevynut
Hey thanks, some day I will explain how we pulled all that off.
In the interim I wonder if thru an exchange of piecmeal parts and exchange of common bearings it would be possible to make it look normal and get back to the six lug 16 in wheels.
I suppose I could go to a driveline shop and have the driveline shortened, have new springs fabricated that would allow the wheels to align in the fender opening.
A point I didn't mention we fabricated with a, welder,a Ujoint part truck and part sedan, because the splines were different.
I laugh, tongue in cheek, about Ujoint problems I read. Besides running the heck out of that truck at freeway speeds daily, I would continue with that very cobbled up joint.
Incedently I parked it as I was concerned about preserving and restoring, after witnessing several freeway accidents.

The torque tube for a car will not fit under a pickup (without modification). The spring seat is attached to the axle differently. Biggest difference is that pickup ring/pinion has a different point of center than the car. I think the rear end in the pickup has hypoid gears, with the pinion meeting the ring gear at the bottom of the circle, giving more ground clearance under the axle.

Hey Gregg
Thanks, after spending the past 2 weeks checking out every source and site, and visually comparing you are right. I got by with a lot of fudging when I resurected this poor wretch, however it don't look promising on the Diff swap, Oh well.
What a Museum piece you created, that 37 Pickup (Oscar) is nice, real nice. I won't attempt to restore mine in any similar manner, as too much of the metal is fatigued in to many critical areas. Your vehicle is "Judged" every time you drive it. They just are not as critical, when you go by at legal speed. Just remember this: you get a best of show with a thumbs up. I prefer them to trophies. Oh 3 speed or 4???

3 speed with 3.36:1 gear ratio. Ring and pinion were produced by a VCCA member in early 2006. Not enough road time on it to comment favorably yet. Only have about 300 miles on it in the mountains near Grand Junction in 2006. Had to spend too much time in 1st gear, and missed the torque I have in my 37 car with a 4.22:1 ratio.

I think may answer may be wrong. I the car has the the torque tube and pinion sitting lower on the differential and ring gear. This allows for a lower profile or height of the car and makes it easier to enter/exit, usually without stepping on the running board.

The trucks have the torque tube higher for more ground clearance.

Sometimes over the winter I will be putting a 5 speed and modern rearend in my 37 p/u so it will be available cheap,I am in Ohio. Jeff

The 1/2 ton trucks switched to a hypoid rear end in 1940. It had nothing to do with torque tube clearence but rather the hypoid gears are stronger than spiral bezel. The axle housing hangs down deeper than the T.T.
The hypoid in cars allowed the floor to be lower to reduce or eleminate the center hump in the back floor.