Ford Expedition Rearend problem

[Slacker]

I have a 98 Ford Exp.Eddie Bauer 4WD (just turned 100,000miles )and recently the rearend has been kinda of skippin or chattering when you go around a sharp turn after standing still. Only does it after it has been warmed up. Correct level and type of fluid in rear, u joints ok. I was told it was that the clutches are slipping in the rear. Could this be it or is there something else? Any help would be appreciated. Thanks..

[randy77zt]

pull the cover and drain it.go to ford dealer and get the correct lube and 2 bottles of ford friction modifier.the cover is siliconed on .scrape and reinstall cover.remove fill plug and abs sensor on top of axle.pour in the friction modifier in the abs sensor hole then fill thru abs sensor hole until oil runs out fill hole.reinstall sensor & plug.or get your local ford dealer or good private shop to do a rear axle service for 1 hour of labor only.shop labor rates are much cheaper in the south than in california

[SnoopJonnyJon]

I routinely have the same problem with the posi in my 98 3/4 ton Chevy. Nothing wrong with it, just need to change the fluid and put in the correct positraction "friction modifier"... can't remember what GM calls it, but i'm guessing its the same deal. What's happening is that the clutches are locking up (not the problem with slipping that you stated in your original posting). If the the clutches slip, you just end up with an open-diff same as most vehicles. What you experience now is basically the same as if you were running a spool in it.