Rear Diff Advice Needed

[mecheng2]

Alright, so I'm about 9 months into owning my 2003 XLS. I just went over 80,000 miles on it. I purchased it with a little over 72,000 and right after buying it (less than 500 miles) I heard the infamous whine from rear end under load at about ~55-60 mph. I talked to the used car dealership and they agreed to rebuild the rear diff at no cost to me since it was less than 1000 miles. All was good until about a month ago when I noticed the noise was starting to return. I changed the rear diff fluid with some fresh Mobil1 and the tube of additive. A little quieter but still not like it was. My question is if they might have rebuilt it wrong, didn't replace all of the right components or something, or if there is something else that would cause the rear diff to wear out again in only 8000 miles?? Also for others who have had theirs rebuilt, what was the average cost? Is there much savings if I pull the diff out myself and bring it to the shop or is the majority of the cost the actual rebuild itself. I really like this truck, but it's hard to get over the loud whining at highway speeds, pretty annoying!! Looking for any help or advice!!

 

[gamecocks]

i believe the problem that causes the whine is the backlash isn't set properly, apparently its an easy thing to f*** up.... but that doesn't mean its tearing up and will break in time, it'll be fine roll the windows up lol
Someone else will be able to shine more light on it but there's a lot of threads that talk about this so search and you might find an answer for your self

 

[matt0248]

My 02's whined from the day I drove it home from the dealership with less than 50 miles on the clock. I had it rebuilt last year with about 78k miles on it. The clutch packs were gone and the pinion bearings were on the way out.

 

[mecheng2]

I've read some of the threads on hear about the rear diff (actually how I diagnosed it originally), but I'm just surprised this only lasted ~7,000 miles. Is there a replacement rear diff that I could go with (locking?) that might be a little beefier? The noise is very audible to anyone in the car, even with the radio on, granted I can turn up the volume to drown it out, but if there are others in the car and we want to talk that doesn't work. Just looking for ideas/suggestions.