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).

 

My uncle had a similar chatter at low speeds and at down shifting or braking. His problem was a U-joint though. He bent the U joint at the drive train. I can't remember if it was at the rear end or the tranny. It stayed together, but the noise was annoying.

 

Thanks for the help, and mine is out of warranty, so let me know when you find out what the problem is! Thanks again

 

Had the same problem three times. Took it into the dealership with 30000 on the truck for a rear end chatter felt it in the parking lot after pulling out of my spot. Dealership kept it over night went back the next day truck drove fine.
13 months later the rear end started to do the same thing. Called bill brown ford in livonia mi. and informed the service manager of what the problem was. He then stated to me that my vehicle had never been in their garage for a rear end chatter before. So i end up going home and finding the invoice and calling them back and magically they found it also. The invoice state they added friction modify. redoped the cover and sent it out. well R.T.V. gave out and was leaking at the bottom of the pig. BIll brown took the vehicle again and did the same thing.
Now i have 54000 on the truck and the rear end started leaking again. Tired of the dealership just adding supplements ,plan on blowing the whole rear end up so everything gets replaced.
I dont mind doing the work myself AFTER WARRENTY but now im tired of it happening every 10000 miles.