Kevin Lahmers

I am getting a little chatter on turns in my 2004 f150. The rear end was redone a couple years ago (according to previous owner) and the right rear axle seal was replaced last winter. I assumed I needed to add some friction modifier. I went to open up the fill plug and oil started to come out. So, I put the plug back in and walked to my computer, searched the forum and then decided to post the question. Should I just drain and then siphon to the approptiate level (1/4" below plug) and then add in the friction modifier? Do you think that this indicates the gear oil was over filled or does it mean something else is going on like the oil isn't getting everywhere it should and so it is too high in the main space? How would one overfill that? Fill it while parked uphill? Fill it from the top? So many questions.

Phyer Phyter

Your diff being over filled as you described will not hurt anything. You may want to drain some only to make room for the amount of additive you want to add. Find out if you have a ltd slip diff. If not - adding an additive will be of no benefit. If you do have ltd slip diff it MAY help but chances are it wont. You likely will need your ltd slip clutch packs replaced.