vibration

Start with the free stuff.. Check your ujoints for any play (watch the joints while you rotate the shaft back anf forth. If the joint moves, it's junk). I only use Spicer joints. Most offshore parts store ones are not very well made. Check the tranny mount. I usually just replace witht eh urethane insert an you'll never need another one. Checl you pinion angle. This is the diference between the centerline of the transmision output and the centerline of the pinion gear and it's measured with a magnetic protractor with the vehicle on it's wheels with a driver seated and 1/2 tank of fuel. If the pinion is not pointed "down" in relation to the outputshaft, shim it to reach about 4° down. Mr Gasket and Lakewood make shims, and 4wd shops can get them easilly. If that is all done and you still have it, the shaft can be pulled and checked but in most circumstances it will be one of the other three things.