I have a 2006 explore that my sister cooked the rear end on. axles gears everything needs to be replaced 2700 for parts and labor at the dealer. a friend of mine has a 99 explorer anyone know if the axles are interchangeable? was gonna swap the whole unit out to make things easier.
i gotta check gear ratio. but i read somewhere all the explorers use a 8.8 rear end. any info would be great!!

 

Yours is an IRS unit, so really it should just be the center section that needs replacement. Not interchangeable with the earlier straight axle, which was used until the 2001 model year.
You should be able to get a used one without too much expense, but I have to wonder if it may just have an axle shaft issue. It's rare to completely fry a differential. If she spun it a lot in sand or snow that could do it, or if it had a leak that went undetected and burned up from a lack of lube, but normal use doesn't generally cause differential failure.