I've been having problems with my truck. It started with a loud clunking sound while I was driving down the rad so I drove home real slow and hoisted my rear tires in the air. I turned the tires with my hand and for a little while both tires would turn. Then after a few seconds it stopped and only one tire would turn at a time. I started it and put it in gear and there was a loud clunking sound coming from the rear differential where the drive shaft connects. That and the tires would not spin. Do you think this could be worn out U joints or could the rear differential be shot? Oh and if it helps it's an 87 Chevy pickup.
look at it..you can see if u joints r busted...is the drive shaft still connected....you may have busted ring and pinion or spider gears...or maybe axels...[now. what were you doing??burn outs?? jumps? dune buggying in the mud??]
could be both, u joints are easy to tell if there bad, should have no play side to side or up and down
you probably blew the rear/or an axle/take drive shaft off and that should tell you if its rear/
you have limited slip rear end. it could be that the pinion gear nut came loose or a u-joint is bad.
One part name that you will grow to hate... Gov-lock Your truck has a limited slip rear end but in those years GM designers tired a newer unit known as the gov lock and its the sorriest P.O.S ever made. Sounds like your just broke. I had to replace the one in my G/F's 1987 suburban just a few mo. ago.. On hers every time she started off the rear would bang and jerk.. I pulled the cover off and metal gear teeth was missing from the side axle gears, the ring gear, the gov loc unit was cracked in half, teeth was all over the magnet made on the cover, bottom of rear housing, etc. Her's only had a stock 350 v8, 2wd, no off road use, 130K miles Good news is junkyars are full of chevy/gmc trucks you can snag a rear end from.. I went to a local pull it yourself junkyard and cut a rear end out of another one in less than 15 min, got it for $75.. Used a 18v cordless sawsall, and angle grinder to cut clean through shocks, leaf spring U bolts, brake lines, driveshaft, etc
