My Ram recently got the diffs serviced. It had one bottle of the friction modifier added. Now when I have driven it enough to warm it up,I get some chatter when turning hard to the left. It doesn't seem to do it on right hand turns. I get no chatter when the truck is cold. Should I add a second bottle of the friction modifier?

I've got a similar problem on my 72 Road Runner. I've run it with two different sure grips (a cone and a clutch) and it always squeals the tire on a left turn. Never on a right turn. Running a single bottle of friction modifier and wondering if I need to add a second, or if there is some other mechanical issue.

I would add another bottle, especially because it sounds like someone other than yourself did the job. I once used some pep boys sourced 80-90 with bottles being labeled "For limited slip differentials". Needed the little bottles too.