Amsoil Slip Lock

[buck91]

So changed my rear dif fluid today; dumped the break in gear oil with Motorcraft friction modifier and replaced with Amsoil severe gear along with 4oz of their "slip lock" LS additive. I know the amsoil has it already, but it took 8oz of the Ford stuff the settle down my posi on the initial fill.

Anyways, noticed something very peculiar. The only other limited slip friction modifier I've ever used is the Ford stuff; I have used it on a number of vehicles with Ford Trac-lok dif's over the years. And it stinks. Badly. Makes the gear oil smell like flowers in comparision. Whats weird is that the Amsoil friction modifier didn't have any noticable smell to it. At least not to my nose. And certainly nothing like the Motorcraft stuff.

Whats up with that? Makes me wonder if there is some real differences between the two, despite the fact I've always heard that FM is FM is FM...

 

[440Magnum]

The stink in gear oils is usually from the extreme-pressure additive (sulfur based). If LS friction modifier has a stink, its because it also has EP additives in it. The LS friction modifier doesn't smell strongly by itself.

 

[buck91]

Yeah, thats about how I had always figured it- still very curious that the MC stuff is pungent while Amsoil is not.

 

[Chris Meutsch]

I changed my friend's manual gearbox oil with factory Acura MTF and remarked at how bad it smelled when brand new. I would imagine it's normal as it sounds like it is based on the above posts.

 

[userfriendly]

What does Amsoil call their TO-4+ fluid, Caterpillar Slip Lock?