Differential Additive?

Seiken1 · #1 03-08-2011, 06:34 AM

On my ranger, I have the 4:10 Limited Slip gear ratio on the rear differential and I just drained it to clean. I was wondering if before you refilled it, you would have to put a certain kind of additive in the oil as I know on some other vehicles you do.

01_ranger_4x4 · #2 03-08-2011, 06:40 AM

yes, the limited slip diff requires the friction modifier additive.

oldcarfart · #3 03-08-2011, 07:00 AM

Quote:

Originally Posted by Seiken1

On my ranger, I have the 4:10 Limited Slip gear ratio on the rear differential and I just drained it to clean. I was wondering if before you refilled it, you would have to put a certain kind of additive in the oil as I know on some other vehicles you do.

I use the AMSOIL additive, but get the Ford stuff at your local dealers parts counter.

Seiken1 · #4 03-08-2011, 03:35 PM

Thanks guys

sgtsandman · #5 03-08-2011, 09:57 PM

If I remember correctly, you should put 4 ounces of the additive in but verify that. I have an open differential so I don't have to worry about it and I'm working off of memory.

corey stevens · #6 04-08-2011, 01:30 AM

or you can just get a good quality gear oil that already has it in it like valolien SYNpower . thay will say limited slip right on it

RAT Ranger · #7 04-08-2011, 05:00 AM

Ford/Motorcraft friction modifier (also known as "skunk oil") PN# XL-3, is around $5 bottle & I use 2 bottles in my L/S.

It can also be used in automatic trannys to firm up the shifts.

Badmotorfinger1 · #8 04-08-2011, 06:50 AM

Quote:

Originally Posted by corey stevens

or you can just get a good quality gear oil that already has it in it like valolien SYNpower . thay will say limited slip right on it

Royal Purple makes a great gear oil, also with the friction modifier. It's a bit pricey, but I picked up 1 MPG after draining the old and refilling with RP.