Hi all, I'm new to this forum and wish to ask for some advice from others who have these rigs. I've owned my 1976 Jimmy 4x4 for 19 years, and have had good luck and alot of fun with it. I rebuilt the motor 10 years ago, and have put a couple transmissions in. The vehicle has 200,000 miles on it. Here's the problem. A month ago I started hearing noise from the rear axle area sometimes. In the last week the sound got worse(tinging metal sound), so I lifted the vehicle and ran it in gear with the diff cover off. The ujoints seem fine and the outer bearings are 2 years old and seem fine also. The sound happens only at take off and under moderate driving load. I couldn't see anything or hear anything wrong while it was in the air so I put the cover back on and filled with new 80/90 wt(it's a 12 bolt cover). Today I drove it to a reputable shop to let the mechanic hear it, but now the sound is virtually gone and there's a new symptom. The car is vibrating or shaking in the rear and it feels like it's coming from the rear axle(I'm not rough on the vehicle and don't think it's an axle issue). The mechanic says it could be spider gears? I am a muscle car restorer, but have never had to rebuild or service a rear axle. The mechanic says I should buy a differential rebuild kit and try to fix it myself. I'm a bit intimidated and don't want to get in over my head. Also I am not sure why the axle could be shimmying now when under driving load and the sound be almost gone now. Any ideas or suggestions would be appeciated . Thanks, Darren...

 

I went to past threads on this subject and have decided to do another inspection of ujoints and outer axle bearings for wear. If I don't see anything obviously wrong I will replace the ujoints anyway as a starting point. If that does'nt fix the problem at least I know there good. If the problem is the same I will pull the axles and check and probably replace the outer bearings. This way I at least know these parts are good. If that does'nt fix the problem, it will have to go to the shop. I figure this way at least I know whats replaced, and saved money by doing these myself. Hopefully the problem will be solved. I will update as I work on these items.

 

This time when I inspected the driveline I was able to feel and see a bit of play in the rear u joint. Problem solved! what a great feeling to find the problem and fix it myself. On the (or off) road again!!!