It start''s when I put the car in reverse then goes away after driving for a few blocks I put new wheels on and it was better for a month of so then it came back and is getting worse. Please help.

maybe something to do with the rear diff or driveshaft

Ever checked/changed the diff fluid?

checked the level, did not change.

do these rear ends go out? car has 140k on it.

well with neglect to them and 140k it is possible

But generally, no, diffs don't fail. I've got 140 on mine, no issues. Don't hear of diff problems very often. And by not often, I'm talking twice in 15 years.

same here, the few guys I have talk to,say drive it until some thing truly breaks.