Hey everyone, I'm planning on changing my rear diff fluid out really soon, but I'd like to make sure I've got all my bases covered first. I've found out that I have an LSD, thanks eatsleepdrivesc for finding that out for me. Now I'm aware you need a friction modifier for the regular oils, but I've been reading the forums and the web and I know that Amsoil and Mobil 1 both have friction modifiers in them already for LSD's. But, do I need to buy more for the change or not. I love mobil 1 and would like to go with that. Any personal advice? Thanks a ton!!!

 

I'm running Amsoil Severe Gear Synthetic in my differential. Amsoil Severe Gear does not need the friction modifier, but I put 4 ounces in anyway. I made the switch to Amsoil at 30K. Pulled the cover again at 45K, and the darn stuff looked as clean as the day I put it in. I'm at 65K now. At 60K I siphoned a tad out just to check the clarity. Still looked good.

 

So I can add friction modifier and it won't do anything even if say mobil 1 or amsoil already has the friction modifier? But I guess I've got to take out some Mobil 1 or Amsoil because I can only have so much before it over flows.

 

Yes you need it! Read the owner's manual!!!

I use Mobil-1 and the friction modifier. The manual calls out the use of synthetic oil AND friction modifier.

Hell, the stuff is only $6.00 a bottle. Buy several and keep them on hand for future changes.

H.H.

 

I just changed mine a few weeks ago and I used the Royal Purple of the recommended weight. It also had the modifier in it. I was going to use Mobil 1, but saw that the purple was a few buck$ cheaper, and have heard good things about it. I'm happy so far. I also installed a PML Diff cover that brought the fluid capacity up to a full 3 qts.