My 1998 Montero has been at a rear-end specialist in Los Angeles for over a month now, and they still haven't been able to diagnose a whine in the drivetrain from the rear of the vehicle over about 50mph. They swapped out the rear end and the noise has mysteriously remained. They also swapped the front dif. after it started making noise. The front is now quiet. I am not sure how to proceed as these guys were described as the best in the area for any kind of differential issues. I also took it to a transmission shop that confirmed the noise is coming from the rear, not the tranny. I was told someone in the shop wants to buy it off of me and not concerned about the noise. This is a 1998 Montero with the rear locker, and about 150,000 miles. I have seen similar vehicles on Craigslist for exorbitant sums recently (over 15k), not sure if people are actually buying these. My original goal was to fix it up and drive it for a few seasons before selling it off, not sure if I'll be able to sell it for a good price with this kind of noise. Any advice on a way to resolve the issue, or should I sell it to the mechanic? I'm not against holding on to it for a bit longer, but the repairs have started to add up.