Can anyone tell me why the rear end in my 1994 Mustang may be making noise. I'm not sure which rear end it is but the car is a 6 cylinder, 5 speed. We had it at the shop the other day and the mechanic said the axle bearing were going out. I have replaced them but the noise seems the same. Could it be something else? I have also been told that I may need some special sort of gear lube additive. I'm lost, any help is appreciated.