Thread: Please ID Trans
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Old 02-10-2022, 11:25 AM   #2
MJN
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Join Date: Feb 2000
Location: Maquoketa, Ia/ Orr, Mn
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Re: Please ID Trans

Its not a SM420- it looks to be a 'crash box' or sliding gear or simply the GM four speed transmission, the unsynchronized trans used before the SM420 came out. There should be a stamped code on the case at the rear edge of the top cover.
Is the case casting number 590474?
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