When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I was talking with a Ford truck enthusiast the other day and he warned me of a potentially rear end killing problem with different differentials.
He said that there are two rear ends, one takes regular gear oil and the other takes synthetic. And if you put synthetic in the regular rear end you'll kill it within a few miles.
You need to find out from ford which you have and use the correct fluid.