Reign To check a u-joint put the parking brake on and OUT of gear get under it and shake and push and pull with all you have on both ends of the driveshaft.. ANY movement or "slop" in the joint is BAD! If one on a shaft is bad do em both..
The other thing to look at is to jack up one wheel at a time and turn it by hand and shake it by hand listening for the bearing to make the noise.
If the noise is in the rear you can put stands under both sides and start and let her idle in gear while listening to the different parts.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />