Brian71583

Lately I have been noticing my rear diff (I am assuming) has gotten louder. It is def. speed related and is a little louder when NOT under load (coasting, decelerating)

I dont know how to describe it. Its kinda like a rumble I guess.

I just changed my fluid and it didnt effect it at all.

Any ideas?

KD4315

It could be your pinion bearing. I had a bad one and my rear diff had a grinding noise in it.

Bustedknuckle

+1 on the pinion bearing. Check the fluid level and condition too.

Brian71583

Old fluid level was good... condition was dark but nothing really abnormal. No metal in the diff.

Im going to go out in a few minutes and try and move the driveshaft to check the pinion bearing.

Also, I only noticed this since I removed my front driveshaft.... but this noise/vibe is coming from the rear. Could one have to do with the other?

Best way I can describe it is it sounds like a Jake brake from rigs but obviously not loud like that.

VTJeep

Rear DS u-joint good?

94XjSport94

I'll bet on a bearing too.

Brian71583

It's wet around the front of the diff but old fluid level was good and I don't feel any play trying to move the ds.

mikeoc1

I have had two non-jeeps show those symptoms years ago and had to have rear diffs done on both.