No announcement yet.

Diesel Powered M37

  • Filter
  • Time
  • Show
Clear All
new posts

  • Diesel Powered M37

    I just bought an M37 with a Detroit Diesel engine. The truck is very nice, but I am trying to determine a few pieces of information. The engine and transmission were originally intended for a Gama Goat. The transmission is a four speed with reverse down and left. I have read that it could be a GM 420 or a 465. I need to do some work on it, and need to know how to identify it. After doing so, I need to source a PTO for this transmission. If you have any info on this transmission, the pto, or have a source for winch related parts, please let me know.

    Please see my add in the classifieds, because this truck would be a lot better with a winch!!!

    Attached Files

  • #2
    It looks like a GM SM420..
    The easy way to tell an SM420 from a SM465 is the length.. the 420 has a case length of 10.5" the 465 is 12"
    also the 465 has two PTO ports and the 420 only one on the drivers side.

    I personally run an SM420 in my 1948 Willys Jeep.. I like the super low first gear (7.05:1) but there is a large gap in the gears between second and third, with a Diesel I would say that a 465 would be a better choice


    • #3
      Do you happen to know the approximate year ranges that these two transmissions were used?

      I seem to recall that a 1980 Chevy pickup I had was equipped with the SM465; does that sound right? I am curious when the SM420 was used.
      Power Wagon Advertiser monthly magazine, editor & publisher.

      Why is it that the inside of old truck cabs smell so good?


      • #4
        PTO source

        Do you know where I could get a PTO for this transmission? Does anyone have a used one? I guess it should be pretty easy to get parts for.

        Thanks for the id.


        • #5
          the Sm420 was used from the 40's up unto 1968 in Chev's and GMC's up to 2 ton.. the 420 was available with a brake on the output.
          there was a year or two when Chev used a NP 435 then the SM 465 was used up to around 1988-1990