The Stovebolt Site Forums The Shop Area Driveline SM420, swap in syncro guts torque tube case?

Mcatt,
Your tranny is not a SM420. As others have said, there is nothing interchangeable with your tranny and the SM420. SM420s where used with torque tube driveline, but your torque tube would be too long and would require modification to fit a SM420. Alternatively, you could modify your driveline to open drive and use the SM420. Both choices are difficult and require professional skills.

Let me ask why do you want to change out the tranny? If it needs repair that is the easiest solution . If you don't like to double clutch, I would encourage you to practice more until you are good at it. Once you get this skill, you won't want to go back as it is part of the character of these older trucks.

Kent