Sometimes clunk from rear end

[Ruby Fan]

I was in heavy stop & go traffic, and noticed that when I had to give it some gas to advance, slow pace, I heard a clunk sound coming from the rear. It didn't happen every time, just when it went from a paused creep. It was warm outside, and this is the first time it caught my attention. Do you think this is normal? Or maybe needs some rear diff fluid? Thought I would run this by you folks, before I put it on a lift. This is for an '85. Any opinions? thanks.

 

[tmkassin]

Sometimes the rear brake calipers can make a noise. It sounds more like a click. Sometimes they get a little sticky, especially if the car has been sitting a long time in storage.

 

[John Robinson]

I know you have an 85 and this is for a 93 but I would guess there is somthing similiar to this supporting your mufflers or exhaust.

Go to this site

http://www.corvetteactioncenter.com...ump-when-going-over-sharp-bumps-resolved.html

 

[roscoethug]

I have an '88 Auto and get a definite 'clunk' but only when it shifts from 2nd to 3rd or when coming to a stop. Those are the only times it makes the noise. Changed the diff lube per instrux, and no difference. Lived with it since 1993.

 

[Chas]

I had a clunk from my rear end and tried everything to get it under control.To me it sounded like a rotor "popping" thru a caliper at slow speed or as you release the brakes and just start to roll. I did the following on the advice of a friend.

I went to the GM dealer and purchased a $12 bottle of "posi" additive.The rear end has clutch packs that have to lubed right or it will clunk. It took less than 10 minutes to squirt it into the side of the hog and then to a parking lot to do some figure 8's and really work it in. The noise went away and i have not heard it since, that was 4 years ago. The only thing is,it HAS to be the GM fluid and not some knock off crap.
Maybe I'm way off base for your situation, but 10 minutes and $12 cant be that big of deal for you to try.
Good luck.