Diff and axle problem

[Ren]

Well the car went to the garage that supplied the box and they took all the work I did apart and found no problems in fact I was told i did a good job. Tested the car and was told that those noises are normal for a car with no sound proofing but that did not explain why the wheels locked up in reverse and did not explain why those noises were not there previous to me doing the brakes and Large O rings. I noticed that the car vibrates badly at about 20 rpm and was told that it sounds like a flywheel or clutch problem. I think its the main shaft in the box. I now have to remove engine and look at the flywheel which I beleive is pointless exercise but must eliminate all possibilities. The car is still nocking on bumps and still making winey rotor blade sounds rom the box. I tried conatcting the PCGB 356 tech man but no help after telling him who did the box (keeping the faith).