The only real difference between 3 on the tree steering columns is the attachment points for the shift box in front of the firewall and for the shift lever knuckle just below the steering wheel. There are two different PN's for the jacket, one for 4 speeds without the attachment points and one for 3 speeds with the attachment points. You could cover those holes or weld them closed and grind smooth before repainting. But as far as the transmission itself, the 4 speed will bolt in place of the 3-speed. You'd need to be sure it has the u-joint and ball housing socket on the rear. You could find a donor 4 speed on most big bolts. Should be lots of those in farm country.
[on edit] Kevinski has some good points. Floor seal is different (I think both are available from the usual vendors.) Later 1/2 ton's didn't have a transmission mount crossmember (my 51 does) which brings up another question on the length of the trannys. It's possible that the 3 speed is longer, which would require a longer torque tube for a 4-speed. Can't tell from the parts listing whether that's the case. Nope: Only 1 differential housing and torque tube listed for 1/2 ton's with manual transmissions. A truck with a Hydramatic Transmission would be different.
Last edited by klhansen; 07/14/2026 11:22 PM.
