I have an EL XR6 and the diff is starting to groan when i turn corners. At first i thought it was the power steering but turning the steering wheel when the car is stationary does not produce the noise, and it sounds like it is coming from the back of the car. It also makes a chattering-type noise on rough surfaces at lower speeds. According to the service guide it could be a lubrication failure where the oil used is the wrong grade specified. I had the diff oil changed about 2000 kays ago by my mechanic and he told me used the correct multi-grade lsd oil for it. Is this noise a common problem with this type of diff? What would anyone roccemend i can try before I start getting quotes for a recond xr6 diff?

Ford make an additive that should be used when the diff oil is changed. Go to your local dealer and ask the spare parts guys. If those desk jockeys have not heard of it, rip around to the service department and ask them.
Its best to flush out the oil and change it with a good LSD oil (LSX 140 rings a bell), put the goop in and go for a drive. You need to do figure 8's to work it into the LSD mechanism, 10 or 20 of em. Geez I used to have fun doing that in XR8's etc in a K Mart car park!!

Thanks a lot, will see what Ford say. If additives fail might be in for an expensive trip to the diff shop!

Have seen it fix some pretty noisy diffs!!

Took my car to W.A. diffs today and they put new cones in the diff for me. They said the old ones were worn but nothing beyond usual. Sounds quiet as now! Hopefully it will continue to run that way after the new oil settles in.