I found the worst part of the job was the remove and reinstall part - the SM420 is heavy with a round bottom. Since it's out rebuild it using one of the kits.

Search for bk108 sm420 and you should find:
https://www.transmissionpartsdistri...7-gm-4-speed-with-10-5-case-1-pto-bk108/


Gord 🇨🇦
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1954 1/2 ton 235 4 speed