Originally Posted by Southerncomfort
I have a 2005 XLT f150, and the rear differential has been giving me problems. whenever I go on a long drive and the truck has been running for a long time or if i have been towing my boat it only has this problem but now its starting to occur more often. The problem is whenever i come to a stop and then start driving again, the rear end chatters until i get to about 15mph. any ideas on what to do????? i pulled the plug and there were not any chunks of metal stuck to the magnet and it had plenty of oil.
Pulling the plug won't tell you anything. What I did was take the cover off, remove all the oil, use paper towels to get all the fluid up then take some brake cleaner and spray your gears down keep paper towels handy to wipe any mess up. You will then be able to see if there is any issues with your rear gears/spider gears.
I had something like you described so I decided to do a proper fluid change. I used royal purple with motorcraft additive. My issue wasn't the rear differential, in fact after $4500 worth of repairs I'm still having issues and my truck was dropped back off at ford tonight (all under my warrenty).