High all.I changed my diff fluids a while ago with Redline & the bottles said that I didn't need a friction modifier to add to it.Now I'm not sure my Limited Slip is working like it used to.Is this "Normal Wear",or do I need to add the Modifier?Thanks.

 

The friction modifier is for differentials with clutch-type posi units. We don't have clutches, so we don't need friction modifiers. I've been using Redline for about 20,000 miles now with no problems.

 

Thanks.I had it out in the snow today,& it was working OK.I was just assumeing that it wasn't working as well as it used to.(Like when I had 5000 miles on it.)I guess it's still working good enough.

 

If it starts chattering on corners when it is warm then you may need the additive. No 2 trucks seem to react the same way so all you can do run it and see what happens.

While the owners manual says no additive needed, the AAM diff has a set of brake shoes that make the TQ bias work and the fluid you use does not have the correct mix of friction modifiers they will start grabbing and cause chatter.