When I put the car in gear it slams into gear pretty hard. I checked the trans mount and it is fine. So how can I tell if the u-joint it bad?
thanks
Tom

 

just putting the car into gear wont tell you if the ujoint is gone, and the only way to tell that is to pull the 4 bolts out of the back of the driveshaft and disconnect the driveshaft, but while you have it out anyways you might as well change them, so just go ahead and do it. and it sounds like its your tranny that might make that SLAM, but i might be wrong, i dont know much about trannies. oh well!

------------------
Jarrad
1990 IROC-Z L98 350 TPI
TH-700R4
G92- 9 Bolt Borg-Warner 3.27gears
Bright Red Hardtop/ Grey "Custom" Interior
NOT STOCK, NO WHERE CLOSE!
NEW RED PAINT and WELD PROSTARS.

DAILY DRIVER: 1991 GREY S10 2.5L/5SPD -FOR SALE. leaving for army.

 

if you hear a metal to metal "CLANG" when you put it in gear, that's a good indication they're bad, at least one of them.
A better way to be sure is to slide under the car(on stands) & twist, shake, turn, etc. the driveshaft, while holding the trans yoke for the front, or the differential yoke for the rear. If there's ANY play in either, it's shot. You'll know it when you feel it.
I'm not sure when GM started this, but on some, with the factory U-joints, they're put in with red plastic "locks", if yours has this, you'll need a torch to melt the plastic to get them out.