Different sources state adding 4 or 8 oz of friction modifier for each of the front/rear differential (limited slip type, duh) with fluid change. Which is it?

 

Go with the 8oz it cant hurt.

 

8.8 and 9.75 it takes 4 oz. On the 10.25 it takes 8 oz.

 

Thanks, doing front & rear today, along with xfer case and engine. Did the trans yesterday. An oily weekend.

 

If you're using synthetic diff fluid you shouldn't need to add it, a lot synthetic diff fluids such as Royal Purple already have the friction modifier in their fluid.

 

I used ansoil in my rear and was told by the dealer that it had friction modifier in it already and that didn't work so well so I pit in a 8oz tube and drove around for a bit still was giving me trouble so I stopped at ford and they advised me to add one more 8oz bottle and it should take care of the problem 30,000 miles later still no trouble

 

I used the royal purple and added 4oz of friction modifier, I was told if you used too much you would have problems, honestly I'd rather not put enough in, and then add more, but the 4oz worked perfect for me. Make sure you buy a hand quart pump to pull the gear oil in, much easier, and get a twisty funnel to put the transfer case atf in.

 

What oil goes in the transfer case and how hard is it to do

 

Mercron automatic transmission fluid, not mercron V, that's for the transmission. There's an explanation in the owners manual of the difference between the 2. I bought Valvoline dex/mercron automatic transmission fluid as that's all I could find. The dex part means it would work in a Chevy. Anyways its transmission fluid. On the transfer case there is simply a fill plug, and a drain plug. I bought a funnel at auto zone that had a flex hose on it which made it rather easy to fill it up, it is a bit messy, I believe it used about 3 quarts, you just fill it up until it pours out of the fill plug. I changed mine with 90k miles on the truck, and the old fluid was really dirty. The new fluid is red, as with all transmission fluid. You can take the old fluid to a place like auto zone and they will recycle it, just tell them its transmission fluid.

 

Thanks