The Stovebolt Site Forums The Shop Area Engine Shop '37 rear end

Anybody ever change the earlier ('34-'35) rear end to the later '37? I wonder what you would have to change. Backing plates, axles, ????.
ron

The torque tube and driveshaft will not likely be the right length. what are you trying to accomplish? Juice brakes?

More speed. I though I'd replace the ring and pinion in a later ('37 on) rear axle and put it under my '34 pickup. I want to keep my mech brakes.

I don't think you'll gain much if anything. If the 37 is the same as 38 the tallest gear available on a PU is 3.82. Standard is 4.11. If a Master car rearend will fit, it's 3.73.

I know but you cant get ratio change gears for anything older than '37. I'll just have to get one and find out.

The wheelbase is the same on all of the vehicles you mention which means the rear axle and torque tube should bolt right up, at least from that stand point. I would think that by using the hardware from the 34-35 rear end, you would be able to use the mechanical brakes. By hardware, I mean, the backing plates and hubs. I believe the backing plates are riveted on, so you may have to bolt them to the 37 rear end housing, but that should work. The only other thing you need to check is the width of the two different rear ends to be sure the 37 fits right and looks right under the truck. The main consideration here would be the distance between the spring perches because of the way that rear axle mounts to the rear springs with the clamps used for it to pivot and function correctly.

Sounds interesting! Good luck!

Joe

According to Hollander's, the 1937 1/2 ton driveshaft is 6 inches longer than the 1934-1935.

Baldy, I guess anything is possible, but the wheel base is the same. There must be a difference in the transmission components causing the transmission to be 6" longer on the 34-35. I can see where that is totally possible. If so, the transmission would also have to be transplanted. That might be the deal breaker!

If that's the case, this post is toast!

Joe

Drive shafts and torque tubes can be shortened. The engine could be mounted farther forward in the chassis on the 37, four speed transmissions were identicle from 1932-1947.

If I was going to shorten an enclosed drive shaft, and I have done that, I would open up all the possibilties and try to capture some other valuable options besides just the gear ratio. Something tells me that doing that is more than uncleb would want to do. I don't know. :confused:

Joe

The wheel bases on the 34-35-36-37 1/2 tons are all the same however the prop shaft on the 1934-36 models is 52 1/2 inches long while the 37 prop shaft is 59 1/4 inches long.That is 6 3/4 inches difference. The 37 has a different design engine and transmission than the earlier trucks. The earlier trucks shared more componets with the master passenger cars while the 37 has a lot more stand alone componets.

I just pulled the rear end on my 37,1/2 ton. I have not posted them yet in my photobucket but will try to post them by tomorrow. I will take some pics with some measurements tomorrow also if that can help you or anynoe else. I do have pics I took with the perches off and spring measurements also. They will be in the folder "Chevy teardown" you may have to wade through more than a few pages to find picks you want to see. If you have any measurement requests I will be glad to help you out since the garage is only a few feet away and everything is getting taken apart and inspected whether I am going to re-install it or not. I do have some close up pics posted with the cover removed of the rear end gears. Also there are pics posted of the backing plates and brakes.

I have got the photos posted in my photobucket of some of the rear end photos I took with some measurements of the torque tube, spring perch etc...maybe this will give you a better idea of what might or might not fit.