The Stovebolt Site Forums The Shop Area Driveline Will it fit?

I've found a SM465 out of a 1984 3/4 ton. I'm wondering if it will bolt up to my 1957 235. My current drivetrain is a 3 speed torque tube system which I believe is original to my 1940 3/4 ton. I want to go open drive line and newer rear axle. I would like to keep my current bell housing Which has floor stomp starter and supports clutch and brake pedals.

Jim

It might be necessary to open up the hole in the bellhousing. A machine shop with a BIG lathe should be able to do that, but the setup time to get the hole dial-indicated concentric will probably cost as much or more than the actual time spent reboring the hole. A SM-420 would probably be a bolt-I'm swap.

OOPS! scratch the above advice- - - -the 1940 has a different bolt pattern for the transmission and a different motor mount setup. To use a 57 truck bellhousing you'll need to install a 54-up crossmember under the bellhousing, do the above hole enlargement, AND fabricate a bracket to support the pedal mount.
Jerry

Thanks Jerry. That eliminates the 465. If I can find a 420 and go open driveline what rear axle ratio would you suggest for 65 mph comfortably? I'm running 235/75/15 tires. I wont be hauling heavy loads. Going to be my daily driver.

Crowejam, SM465 and 420 have the same bolt pattern, SM420 bearing retainer is smaller than the 465. Jerry was thinking you had a closed-shaft 420 in which case, the bolt pattern would already be correct for the 465 so all you would need to do would be open up the center bore in the bellhousing. The last half of his post, he said to scratch the above advice, meaning that you can't go with a 420 or 465 without going to a newer style truck bellhousing and crossmember.

Oh, ok. Full disclosure here. I'm full time in a motorhome so I have to impose on family members for work space. I'm trying to find a bolt in solution so it doesnt take too long. I know I will have to relocate spring perches for the new rearend and have a driveline built but I really want to keep my 1940 bellhousing. My original plan was to put 355 gears in my torque tube axle but my shop manual says rearend must be removed to do that. I figured if rearend has to come out I might as well get rid of torque tube all together. (It leaks in several places) Is there a open driveline transmission that will bolt right up to my bellhousing?

The only choices you would have will be the crash box 4 speed, or a few passenger car 3 speeds. I believe there are a few options for the crash box that use an open driveline. I've got one for a 1946 one ton that has the open driveshaft.
Jerry

Ok, disappointing news but at least I know where I stand. Thanks for the input, you guys are like encyclopedias for these old trucks!

Hey Jerry, by crashbox you guys mean it needs double clutching, right? I've got about 4 million miles in semis so I'm not afraid of that. If that 46 box will bolt up to my 40 bellhousing I would be interested in doing that.

I don't think a non-synchronized 4 speed transmission will bolt up to your 3 speed bell housing. If my memory serves me correctly, both the center bearing retainer diameter and the mounting bolt pattern are different.

All 1937-early 1947 1 1/2 ton trucks used an open driveline.

Given your situation, I think the 3.55 ring and pinion swap would be the most expedient.

Thanks Paul. This is more complicated than I expected. I'm emailing with Lugnutz re a T5 swap. Still trying to figure out what pattern my bell is..tough to do with trans in truck.