i have a 91 samurai ant i am geting a vibration when i drive anywhere, but as soon as i push in the cluch it goes away. i'v replaced all the u-joints, but its still there. so then i took the front drive shaft off drove around vibration still so not front axle or drive shaft. then took rear drive shaft off put in four hi drove around vibration still there so its not the rear axle or drive shaft. motor is smooth and solid so the motor mounts seem goodthis has got me drove nut's anyone have any ideas. :confused:

Check your t-case bushings also did you replace the jack-shaft joints also?

I had a similar vibration awhile ago. I crawled under to check out the t-case bushings but they were fine. While i was under there i noticed the heads of the bolts on the t-case mount were backed out (one had fallen/taken out completely). I tightened up all the bolts on the mounts (if the 91 is like an 88, don't forget the two bolts hidden next to the frame) and the vibration was gone. I don't know how they ALL came loose all of a sudden (besides someone trying to score a free 4:1 case), but the t-case was flopping around causing the vibration.

Same problem on mine, 4 bolts holding the small mount on had all come loose.
also a crack on one of the chassis mounts on the other side

i checked all the t-case mounts and they all seem good and none where backed off. i took the t-case off tonight and put one in out of my parts rig and its ok now. anyone know what could be wrong with the t-case? thanks for the help :D

Input shaft bearings bad? Check all the flanges for any play (in out, left right).