F350 Dana 80 Problems
Truck is an '02 F350 4x4 Dually 7.3 w/ 108,000 miles on it. Bought it used with 79,000 miles on it..
Anyway, It developed a bad whine noise in the rear end which turned out to be bad bearings / races that caused the ring gear to wear enough to require replacement. I had a good shop replace the R&P and do a complete new install kit with bearings / seals etc. They checked the Limited slip and said it looked great.
After putting about 1,000 miles on the rebuild I have noticed a squeek that is only audible at VERY low speeds when turning. I called the shop who worked on it and they said to add another bottle of friction modifier. (They only put one bottle of it and I found a TSB from Ford that requires 2 bottles of friction modifier for the D80)
Anyway, I addied the modifier and have now put another 300 miles on the truck. The noise has not changed at all... It is very loud and easily heard with the windows down in first gear while turning. It almost sounds like a dry bearing (metal on metal) sqeak. I felt the housing in various places to see if it was warmer than normal anywhere. The only "warm" area was where I would expect it, around the differential. It was only slightly warm, not hot at all.
I'm going to take it back to the shop who worked on it but they are 2.5 hours away from where I work / live now. So it will be a week or two before I can drop it off.
Any other ideas?