fitting Canadian Acme T-98 into a US M37 (non-B1)

[pybyr]

I'm finally starting to get back closer to resuming my long dormant work on my 1951 M37. Truck has 16,000 on it and original paperwork shows engine was replaced by US gov't at 10,000. When I drove it a bit soon after buying it and before diving into some of the work it needed (things done to it before I got it had messed up the charging and cooling systems)(and then I ran short of time and funds and so it has been waiting patiently in my barn...), it'd sometimes pop out of gear going downhill, with engine braking, in second gear. From some postings from Charles T., I learned that that's a classic symptom of a common problem in the early 88950 (pre-NP420) transmissions.

I have kept my eyes open and have just purchased at a very reasonable price a Canadian Acme T-98 from a Canadian M-37, with a 1975 rebuild tag. The T98 is synchroed in 2-3-4 and generally has a reputation as a very beefy transmission, so even though I am usually prefer originality, this seems hard to beat.

I don't have a winch or any other PTO driven functions so that (which I guess is different between the US and Canadian transmissions) is not an issue.

I know (if I am understanding correctly) that the US M37s had a 10 inch clutch, and the Canadian M37s had an 11 inch clutch (and the Canadian trucks also had a 251 rather than a 230).

Also, according to the guy I am buying the Canadian transmission from, the Canadian transmission has a 1-3/8 10 spline input shaft. I have not been able to find out the exact diameter of the standard input shaft on the US transmission, but I am somehow getting the sense that it is likely smaller than 1-3/8.

Can someone please tell me the diameter of the input spline shaft on the US transmission?

And... if I have to get a new clutch disk to match the input shaft on the Canadian transmission, do the US flywheel and pressure plate limit me to an exactly 10 inch clutch? Looking around at available clutch discs, I am seeing many more choices for the 1-3/8 that seem to be 10.5, 11 inches, and larger.

Thanks in advance!

[Tom Petroff]

1 inch is std m 37 input.
Tom

[Matthew Welcher PWA]

I have seen where finding the replacement hard parts for that Canadian tranny can be quite difficult. The gears and input shafts "some of them are rare as hen's teeth." Just a thought for down the road in case of need.

[pybyr]

I have seen where finding the replacement hard parts for that Canadian tranny can be quite difficult. The gears and input shafts "some of them are rare as hen's teeth." Just a thought for down the road in case of need.

Thanks. Apparently the PTO for the Canadian transmission is rarer than rare, but the transmission itself is based on the Borg Warner T98, pretty common, and parts are available. The one I am buying has a 1975 rebuild tag, so as long as I check it over carefully before installing it, and since my truck will see light/ low miles duty, I'm pretty comfortable with it. I'm going to keep the original 88950 transmission so that it is available to return to original. Thanks

[pybyr]

Picked up the transmission today. Seems by any external signs and the way that it shifts to be in nice shape.

Back to my original question, I found a vendor- DC Truck Parts- www.jobrated.com who had on hand a clutch that had been made specifically to be able to put a Canadian M37 ACME transmission in a US truck- so the plate dimensions match the 10" USA pattern but the center is the 1-3/8 10 spline pattern for the ACME. The same person (who apparently has a lot of experience with Dodges of this vintage) says that I'll be able to re-use the existing throwout bearing and the support collar for the t/o bearing- I am almost hoping that isn't too good to be true (given the larger input shaft & surrounding support) but I am going to keep fingers crossed. With other things in life it may be some time before I am able to swap transmissions- this (purchasing the ACME T98) was one of those 'right place, right time, driving distance, good price' that would NOT repeat itself, so it was worth seizing even if it's ??? before I get back into serious work on the truck