68 Camaro with 70 10 bolt rearend. I had 3.43 gears installed and needed a new axle. Also had bearings and seals replaced. When I accelerate or decelerate I hear a sound for just a moment like something is loose. It only lasts for a second or so. I have changed the oil and added two bottles of GM posi additive. Any ideas?

Could it be a bad transmission or engine mount? Maybe a bad u-joint?

P.S. maybe try a more fitting subject in the future. For a minute there, I thought you had a question about a Land Rover "land cruiser"

Sorry about the subject. Thanks for your response. Engine mounts are sound but the tranny yoke may be the problem. There is a little slop in it. The noise sounds like it is coming from the rear end. Could it be drive shaft balance? U-joints are good.

Usually an unbalanced driveshaft will cause vibration at cruising speeds, so I doubt that is the problem. You didn't mention the condition of the transmission mount, have you checked it?

Yes. I put on a new energy tranny mount. I really think it is in the differential. Is it an adjustment? Possibly shims?

Hey guys??? You out there? Wheres BGH?

Can anybody more capable than me give some input?

My only other suggestion is that maybe you've got a problem with your new pinion or carrier bearings. Did you use a new crush sleeve? Does the rear make any other noises other than the clunk? If your sure it's coming from the rear, then either the lash isn't properly set, or there's something loose in the carrier.

If you had somebody do the job for you, than you can only hope that the rear was set up properly. I doubt it's an axle problem since you said that 1 was just replaced.

Sorry I can't pinpoint your problem.