Thread: 47-59 Transmission Swap
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Old 05-13-2020, 10:57 PM   #7
weim55
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Join Date: Jan 2017
Location: Larkspur, Colorado
Posts: 916
Re: Transmission Swap

I did this exact swap once on a 50 3100 1/2 ton. The SM 420 was out of a ‘51 with a torque tube extension housing. Other than switching out the floor plate for the taller four-speed transmission it was a direct bolt in. I changed absolutely nothing else, The original driveshaft and Torque tube worked just fine. If my memory serves me I do believe the yolk and U joint Assembly coming off the back of the SM 420 are unique to the transmission. My ‘51 replacement transmission came with that so it wasn’t an issue but keep that in mind if you’re buying a used unit. Maybe someone on here can chime in about that to confirm.

Steve weim55 Colorado

Last edited by weim55; 05-13-2020 at 11:02 PM.
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