1999 CC DS axle/motor noise

[Dav1774]

Im stuck, got a 99 ds came in with axle noise. it sounds like a gear to gear noise like backlash is out of adjustment. It comes and goes. its very loud in reverse, always there in forward but quiet, if your looking for it you can hear it, feel it alittle too, its not there on deceleration. I opened it, the gears look ok, I replaced all the bearings and seals in the axle (most were good, input shaft a little loose) still have the noise. I took the motor in and had a shop check it, they say the motor is fine.. so I start searching here, most guys say motor spline worn get a centering kit.. ok so I did..but I cant tighten the motor all the way down, not enough room on the spline? tried the rubber bumper but that locked the motor up all together. So is the axle shot? Motor? both?