76vettester

my 76 rear end is making a clunking noise in slow turns either left or right.I cant really pinpoint where it's comming from.I also replaced both u joints on left drive and no help.just woundering if anyone has had a similar problem?Both traling arms have been rebuilt.Thinking bearings in rear end,not sure.

terry82

check your ujoints.

Gilded_Splinters

I had this recently too.

Those large, rubber mounted links at the ends of the leaf spring were toast and bouncing around a bit.

It was an inexpensive fix and easy to do. Most importantly, it solved the problem.

djcwardog

As long as you are looking for worn/bad parts, take a look at the rubber "donuts" that are on the top and bottom of the differential front mount... They are quite often gone and that allows the front of the pumpkin to move up and down causing a horrible clunking sound - related to on and off the gas though, not so much just due to going into a turn as you describe.... Nevertheless, this is an easy thing to check for while you are in that area...

Goody

I would check all the easy stuff already listed and diagnose whether or not it is the clutches in the diff unit.

Also check out the rubber bushings at the shock ends as well as the strut rods.

At least looking at all the rubber stuff is free. Changing the rear diff fluid is another matter.

Binnie77

The noise is coming from the clutches in your posi differential. Go to your GM dealer and get a 4 oz bottle of posi additive, add it to your diff and then go to a parking lot and do a few figure eights to work the lubricant in around your clutches.

Lemans Blue 69

Had a similar problem many years ago. Only after the car was driven for about 15 minutes and only on a turn was when I would get a clunking noise from the rear end. In my case, it was the clutches. This was in 1970. Rebuilt under factory warranty.

79Vette4spd

I put a bottle of "limited slip axle lubricant additive" in my 79 but still have the grinding sound. What is involved in a rebuild? Lemans Blue 69 what factory warranty did you have on yours?
Thanks

glackore

Definitely add the posi additive from GM. Experienced the same problem years ago in my first '71. Most guys ignore the diff fluid and look for the mechanical pieces - ujoints, bearings, etc. Be sure to buy the "GM" additive.

terry82

jack up the rear end .now turn the wheels .look and listen .if you cant see any loose movements or here any thing .your problem may be internal.

cboyd

I had the same problem last year. mine clicked even going straight. I ended up replacing the clutches, problem solved.

C

Eulentier

What is the GM part number for this 4 oz. bottle of additive?

Binnie77

Part # is 992694

Lemans Blue 69

I had the factory warranty. Bought the car in February of 1970 new and had the problem with about 800 miles on it. Took 2 trips to get it repaired but never had a problem sisce.