The Stovebolt Site Forums The Shop Area Driveline SM420 to replace 3-speed in 57 3100 (driveshaft the same)

Mike B,
Based on your SM420 description, I have the 1/2 ton unit. The guy I got it from said it came out of a pickup. All of my transmission/U-joint experience up to now is all from 1946 to 1952 torque tube stuff. My first "modern" open driveline will be this 57. Does this mean that I'd have to find a 4-speed driveshaft to use this transmission? Jim Carter Truck Parts lists ME288 U-joint that fits 3-speed front and 3 or 4 speed rear. They also list ME680 (that they happen to be out of) for U-joint complete 4-speed front. Any way to use 55-59 front yoke and U-joint that fits 3 or 4 speed rear and retain my 3-speed driveshaft? Thanks!