Universal Joint

1931 Chevrolet	Universal Joint (Driveshaft U-Joint)		How-To
	I was assembling my transmission when I noticed that my U-Joint was a little "loose". Now, to be clear, when the plates were bolted together and the assembly was "jiggled", it didn't seem so bad. But eventually, I disassembled it and tried each trunnion bearing on each of the four shafts. Individually they all wiggled a little bit. I tried to find out, "How much wiggle is too much?". I couldn't readily find a NOS 1931 U-Joint (362739), so I began a hunt for a repair solution. What I concluded (with some tips from Chipper and other friends on Chevy Chatter) was that I could use parts from some other years. But it is still a puzzle to fit the proper pieces together. Here's the combination that I ended up with: I purchased a brand new Universal Joint (363717) for a 1932 Chevrolet. Then when I analyzed the individual pieces, it was apparent that they are identical, except for the front yoke. (Click on pictures to enlarge them.)
	1931 (left) - 1932 (right)
	1931 with worn yoke shafts and worn trunnion bearings	1932 with new yokes and new trunnion bearings
	1931 - 1932 Front Yokes - Side View	1931 - 1932 Front yokes - End View

	The 1931 yoke has a square opening for the transmission shaft, while the 1932 yoke is splined for the new, modern synchronized transmission. If you keep the old yoke, then you can use the rest of the pieces from the 1932 assembly in your 1931.
	LESSON LEARNED: As a test, I put the used trunnion bearings on the new yoke. They were still sloppy, with almost the same amount of "wiggle". Then I put the new bearings on the used yoke. It was readily apparent that the new bearings were much tighter on the old yoke. So what I concluded is that the trunnion bearings wear out faster than the yoke shafts.

	Having new trunnion bearings on an old shaft is probably acceptable and solves the majority of the wear issue. So, next time, a simpler solution would be to just replace the trunnion bearings (351888) with new ones. And since they fit 1929-1936, they are fairly easy to find.
	Universal Assembly: 1930-31 AD, AE 362739 1932-33 363717 Front Yoke 1929-31 347661 1932-36 367795 Rear Yoke 1929 347660 1930-33 357493 Trunnion Bearing 1929-36 351888