| Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | Tranny should be SM-420, could have been replaced by SM-465, which are both 4speeds, which started in 1968. Could also be a Saginaw 4 speed if side shift? Could also be an NP-540 if 4 shift rails and Al top cover, or NP-435 if 3 shift rails and Al top cover. Rear could be a Dana 44 or even a D-60, depending on 6 or 8 lugs, no telling what was swapped out, especially if it was originally a torque tube rear-others will have info on that. Do they work OK, or do they need help?
Ed
Last edited by EdPruss; 01/02/2016 5:50 PM.
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
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