Rear differential noise (2001 Pathfinder)

[amb4081]

My 2001 Pathfinder 4x4 has the LSD. After a couple minutes of driving, a noise (like a whirl or whine) can be heard from the rear end. It does not do it at all speeds. The noise is present only between roughly 43mph-53mph, and ONLY under load. If I let off the accelerator, the noise disappears. I changed the rear differential fluid (with LSD additive) in hopes that would help. There does not seem to be any change.

Any ideas on where to look, or is this something I should have a pro look at? I am mechanically inclined (I can change timing belts, water pumps, etc.), but I don't want to get in over my head. Thanks.

[elwesso]

I think the best thing you can do is jack the rear of the car up and see if it is indeed coming from the differential...... Slide under there and see where its coming from...

It seems weird that it would only make noise at those speeds, usually it gets worse as you get faster, starting at a slower speed, rarely does it have a range.

Im almost wondering if a wheel bearing is at fault? regardless,if you jack the rear of the car up, you should be able to tell if its coming from the middle (which would mean its the diff) or the sides (which means a wheel bearing)