cardwiz428

Guys, Book says for rear diff oil Motorcraft SAE 75W-140 and for manual transmission oil Motorracft Mercon V ATF oil. My question is how hard and fast on only using Motorcraft oils. Has anyone used a sub (Redline, royal purple, etc) and had any issues or gained better results. Getting ready to change mine and want opinions..

cardwiz428

Update: I went with Redline for both trans and rear diff...seems to shift easier..

inspecto

I went with Mobil 1 syn ATF for tranny not much different than what came out of it, did not look to bad 55000 miles.

Gabe

I tend to use Amsoil whenever possible.
Just did a rear-diff fluid change on the fiancee's Shelby.
It got Amsoil 75-140 fluid, and both of these, trying to quiet down a dull whine during slow turns.
It worked! She's quiet now!