hi i am changing my reg rear end to a ls in acouple of weeks & need to ask you guys about fluid, i have heard that some synthetics have the additive for a ls clutches already in them
so what brands have it in them & what weight should i buy ????
also should i swap the clutches around kinda diff like some say
thx noel

 

I have used synthetics that said they did and some that didn't have the additive. Alwys seems I have to add some additive anyway.

The way you can tell if it needs some or more additive is to make SLOW tight turns. Usually backing out and turning from a parking space will do the trick.

If the truck chatters, then you need more additive. Usually you will need about 1 fat toothpaste tube full for a full size differential like on a 250/350. You never said what you got.

Chattering feels like a tire rubbing on the wheel well, kind of grabs and lets go several times as you make your tight turn.

I have used both Valvoline and Mobil 1 synthetics in my 94 F250(Sterling axle) and other brand cars. Always needs at least one tube of additive.

BTW don't use too much additive, it will cause the Limited Slip to slip too much and then you almost have an open differential, ie one legged. Just add enough til the chatter JUST goes away.

I never needed to mess with the clutches so no advice.

Good Luck,

Jim Henderson