Just bought it today with 92k miles. Driving home (1400 miles), about half way into the trip I am noticing a rumble coming from the rear end somewhere.

At first I thought it was just tire noise, but at low speeds it seems to be way too loud to be just tires. It kind of "disappears" at high speeds but it may just be hidden by the louder road noise.

Any ideas?

Thanks!

UPDATE:

I took it to two mechanics today, they both suggested replacing the rear diff. / carrier assembly / pinion gear / ring and pinion / etc., etc (second mechanic took a stethoscope and pinpointed the carrier assembly).

I have never worked on a rear diff. before so i'm not too sure about this stuff.

It looks like someone has already put a used carrier assembly on the vehicle, and it is this used part that contains some bad internal components (the cone-shaped housing behind the universal joint has white writing on it).

Should I try to replace internal parts, or just get the whole assembly?

Thinking I should get new part(s) since the last used part didn't hold up. Any recommendations (OEM or aftermarket)?

Also they quoted 7hrs of labor at $90/ hr. Seems a little steep, since they said it's "not that difficult". Is this something I can do myself?

Thanks...