I have a 1999 F-150 that I had the 8.8 rear differential rebuilt about 3500 miles ago. Recently I have been hearing a growling noise from the rear unit so I took it back to the shop that did the work to have it checked out. My mechanic called and said the noise was clutch chatter and to contact Eaton about a possible warranty replacement (I bought the part myself and brought it to him). After contacting Eaton they are saying to replace the oil that was put in it at installation (motorcraft) with Mobil 1. If that doesnt fix the problem then the carrier would have to come out, be sent back to the place of purchase then go to Eaton for inspection, takes 2-4 weeks. Has anyone had any dealings with Eaton parts warranty?

 

why would the mechanic tell YOU to call Eaton... he is the one that assemble it ? WHAT is wheel chatter ?? Personally I think he is spreading BS... Synthetic oil should not have an effect on the operation. Growling noise is normally bearing load , not "chatter".