I did my rear diff a couple of nights ago. This was my 1st time. I used Red Line (what the local Ford Dealer uses). Wasn't too bad of a job, although the oil really smells and I spilled some on the garage floor.... Also, I started with a small hand pump, but it failed about half way through the job and had to move to a long funnel (the Red Line bottles don't have a "nipple" at the end to poor directly in). For the sealant, I asked a number of folks on reccomendations and everyone had their own preferred RTV. I ended up going with Motocraft TA-32, although TA-31 came highly reccomended (but is quite expensive). No leaks yet...

 

Ahhh the oil experts are out.....here we go....

 

I make no claim to know what is the best oil for a differential. The Workshop Manual calls out Motocraft 75W140 Synthetic F1TZ-19580-B. I went to the dealer to purchase Motocraft, but they only had Red Line and told me it met the Ford Specs, so that is what I bought.... I would expect there are a number of good brands that meet or exceed the Ford Specs.

 

You are correct

 

Either way don't go to Napa for it. I needed it quick and went to Napa because it was a 1/2 mile away. Spent almost twice on the caulk tube of the stuff at Napa than a local store I found it at.

The stuff in the caulk tube will do about 8 diff covers. The aerosol can version is easy enough to do two covers.

 

What is the correct oil for the 6 speed tranny?