94 Jeep Grand Cherokee Limited 5.2 V8 (ZJ). Completely stock with 250k miles. All of the drivetrain and suspension parts are original. Plan to keep it stock.
A loud, steady groaning sound from the rear end at speeds from 20 mph and up. Worse at about 50 mph, a little better at 70 mph plus, but even worse when about 30 mph and breaking to a stop. This groaning sound has been around at least 100k miles but has become worse.
There is also a clunking sound when making right hand turns, from a stop, under throttle. This problem's been around less than 2k miles. I’m guessing the noises are related to rear wheel bearings and / or the rear differential gears / bearings (probably bearings).
Wheel Bearings - Last repacked at about 130k miles. A mechanic noted "rear bearing noise" as a problem on an old invoice when the brakes were last done at 175k (brakes working well now with 25% remaining per dealer). I'm guessing he was referring to differential bearings and not wheel bearings.
Rear End - the rear differential leaks pretty bad up at the driveshaft (or is it the pinion?) but has been serviced often enough to not go dry. Original Dana 35 w/ limited slip. And the moaning noise has been present for many years, before the rear end ever leaked.
Question - I'll have to take it to a mechanic. I understand that the rear end and bearings cannot be fully evaluated until taken apart. And I am no mechanic.
Assuming the mechanic finds that the rear diff bearings need to be replaced but most of other parts are good, and maybe the wheel bearings need to be repacked / replaced, would it be better to:
a) Have the rear end rebuilt and the axle bearings replaced (repacked?), or
b) Just get a whole new stock rear end with axles installed (Dana 35, I think 3.55 gears).
c) Upgrade to a new Dana 44 with similar gearing, without upgrading or replacing other parts.
Any idea on the range of costs for a), b) and c)?
And the same question if most of the rear end gears and parts have to be replaced.