Rear End Clunking

[kmanracing24]

Whenever I hit the gas when the RPMs are under 1000 (while I am moving engine kind of bogs for some reason also) something in the rear end clunks until the RPMs match better with the speed. I have a 1985 Caprice 305. Does anyone know what the problem may be? Thanks.

[silicon212]

What you are describing to me sounds like a worn U-joint or two. It's a rattling clunk sound that changes with acceleration. It also projects rearward so it could sound like it's coming from the rear axle.

With the car stopped and your foot on the brake, shift it into drive, then into reverse, then into drive again and then into park. If you hear a loud clunk each time you shift it, the problem is likely to be the U-joints.

[j cAT]

Originally Posted by kmanracing24

Whenever I hit the gas when the RPMs are under 1000 (while I am moving engine kind of bogs for some reason also) something in the rear end clunks until the RPMs match better with the speed. I have a 1985 Caprice 305. Does anyone know what the problem may be? Thanks.

the other componets to check would be the motor and transmission mounts as well as the transmission tail shaft bushing..

[kmanracing24]

Yeah I did what silicon said to try and there was no clunking whatsoever. Thanks for the replies

[j cAT]

Originally Posted by kmanracing24

Yeah I did what silicon said to try and there was no clunking whatsoever. Thanks for the replies

with the front wheels secured/blocked jack up the rear wheels . place vehicle in neutral and manually rotate the drive shaft and inspect for u joint and bushing wear.....also look for grease /rust being throw by the U joints..

If this is ok check the diff oil for level and color if grayish drop cover and clean replace oil...