1996 Jimmy

I own a GMC jimmy I keep getting a loud thummping noise in the rear end when I reach about 50 -55 mph. Sounds like the ass end is ready to fall out, been doing this for almost a year. Anyone out there have any ideas what it could be?? Its almost like its trying to jump into 4 wheel drive on its own.

More than likely your U-Joints are going to hell in a hand basket. Also look into changing your rear diff fluid

Agreed. Getting ready to do mine (weather permitting this weekend) for the same reason. rlith, have any tips or advice (other than not to remove the caps and let the needles fall all over the ground)? :smile:

take some duct tape or masking tape and run it end over end to hold the caps on. When you change them and pull the cap (cup side up!) throw an extra dollup of grease in there...

Actually I made sure the replacement u-joints that I picked up had the grease fitting too. Figured it was a smart move.