I'm getting a rumbling grinding noise from the drivers side rear end. I thought it might be rear wheel bearings so I put in new ones. Car is back together and the noise is still there. I think it is coming from the differential..

My car is a stock 72 Z. Any thoughts on repairing. Is it difficult to change the rear end? I have changed the fuild and it did not make a difference.

Consider (check) the low hanging fruit first. How are the UJoints on the half-shafts? The pumpkin itself isn't difficult to replace. Once man, one day or less.

u joints on the half shaft are good. What is low hanging fruit??

u joints on the half shaft are good. What is low hanging fruit??

It's a metaphor for the easiest to check and fix...

got it. thanks

Manny when you drained the fluid was there much metal filings on the drain plug magnet? Is there much play when you manually move the car back and forth?

If you lift the rear of the car and support in on stands and start the engine and put it is first gear at idle . Can you hear the noise .

BE SURE YOU BLOCK THE FRONT WHEELS. And DON'T rev the engine in gear, just let the engine idle. You don't want to launch your car off the stands.

If the diff is bad locate another rather than having your rebuilt. If your Z is a manual car it has 3.36 to 1 gearing if an automatic car then 3.54s.

Gary

my 73 whines, i'm assuming its the diff. i changed my fluid to royal purple but no change.

Some claim to be able to check U-joints in the car, I never could. I have to take the halfshafts out to get a good idea on the U-joints.

Swapping the diff is pretty easy. There's no big mystery there, just disconnect the shafts and mounts and pull it out and reverse procedure for the new one.

U joints will usually make a rythmic noise when they fail kind of a "hee-haw-hee-haw....repeat over and over" and changes with speed. Grinding is a bearing or gear issue. Also look to see if anything is hitting or rubbing on the shafts or the drive shaft, like the exhaust pipe.

anybody have a good used R180 for sale- cheap?

When I put it on blocks I could not hear the noise. I changed out for one r200, solved the problem. Thanks to all for your input.