I have a 1998 4x4 Expedition that ha developed a grinding noise coming from the rear end of the truck. It sounds like wornout brake pads (metal on metal) but they are fine. Also there seems to be no excess play in any of the wheels. The noise starts at a rolling start and I can still hear it at 70mph. It does seem to get little louder the faster I go. Also engine rpm has no effect on the sound (same at idle or 3000 rpm). When I stop the sound quits. The dealer says pinion gear, but I don't know! There also does not seem to be any excess vibrations from this problem (driveshaft). Any Help????

 

Had the same problem with the wife's 97 Expedition 4x4. Sounds like the two large bearings that support the carrier inside the axle housing have failed. Not too difficult to repair; had to remove carrier and have the old bearings pressed off and new ones pressed on. My Haynes covered the repair process pretty good. Just be sure to clean out the housing of any left over pieces of bearing!

 

I had that on a 97 F150. Both sides just like pima says were bad on mine. Except mine was horribly bad and it got worse as you accelerated, and by the time I got it fixed (just wasn't in the mood to do a rear enderat that time) you wouldn't even want to see the bearings that came out. :o

 

Thanks guys, the dealer has the truck now. I can't wait to see what they find out. I had a man that has worked on 4x4's for 30 years tell me that it was the pinion bearings. I just hope that the ring and pinion does not have to be replaced ($300)! Fred