I use royal purple and don't have "chatter" that I have to ignore..... Just say'n

 

Thanks everyone for input....gonna go straight RP and see what happens. I will update once done

 

I had a little chatter on corners and then put in RP without adding any extra FM. My chatter stopped immediately. Have had it in for about a month now. YMMV.

 

Clean it out while your in there.... Also may be a good time to do axle seals, it's pretty easy and cheap.

 

If you're using Royal Purple make sure you have an actual differential gasket, and take plenty of time and attention to detail cleaning/removing the old gasket and make sure you have some gasket maker/right stuff/silicone, duct tape, mig welder, or anything you can get your hands on to seal that diff cover on flush and tight! Royal Purple oils seem to always find a way to leak out! As far as the additive.... You don't have to add it in but I believe it helps. Might just all be in my head but if it makes me sleep better at night knowing my truck is rollin down the freeway nice and quietly, I'll take it!

 

Update: Truck is sounding alot better.....no more grinding and chattering. Thanks for everyones input