Differential Fluid Additive

A few months back there was a thread regarding changing differential fluid. One post mentioned using an additive if you have a limited slip. I have a dented cover on my 8.25 and am going to replace it. I have a 99 with a limited slip. What does the additive do? Does the dealer put this in when they change the fluid? Thats where I have had it changed in the past.
I don't recall seeing it listed on the bill. I also don't recall hearing this ever before, but that doesn't mean anything. I don't get out much.

Thanks.

The additive properly lubricates the clutch mechanism in clutch type limited slips. Without it the limited slip will tend to lock up more and you will get excessive clutch wear. Some diff fluids have the limited slip lubrication already in it, they say so on the bottle. If the you use a fluid that does not say for lmited slip differentials, then you have to use the additive.

Most parts stores carry it, comes in a little 3oz bottle, Kendal is the one carried around here mostly. Ford and GM both have their brands also that you can buy over the counter. Not sure of the additive for the factory LSD but the FSM for my 98 says a container of 'Mopar Trac-lok lubricant modifier' needs to be added and to make 10-12 slow figure 8 turns to distrubute the modifer thru the clutches after you fill the rear.

RichP said:

make 10-12 slow figure 8 turns to distrubute the modifer thru the clutches after you fill the rear.

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I wonder if anyone ever, or has ever, done this.

I had an old FSJ, that would chatter like the dickens. Spent alot of time driving around in circles, trying to get the clutches to lubricate. Generally chattered, after it had been parked for extended periods.

Thanks, I will use the additive.

DXJ said:

I wonder if anyone ever, or has ever, done this.

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I have!