those are 2 most well know name brand of the shelves that easy to get at any local part store, even walmart, those 2 brand i use the most in my life, so im suprise i saw the new label.Just because those 2 have it, it does not mean all gear oils come with LSD additive
Depends what type of diff you have. A cone type diff requires it as well as some clutch type diffs require FM. A Detroit locker doesnt need it neither does a Wave trac. The best advice is to check your owners manual to verify what type of FM is needed as well as to how much.I've been using Quaker State in the steel drums for over 20 years and never had to add anything to limited slip differentials.
My 07 F150 has an open rear end and I use Valvoline 75W140 synthetic gear oil in it. It has LS additives and my differential is still going strong with 160K miles.Use the least about of friction modifier needed to eliminate chatter.
Just because a gear oil comes with LS additive doesn't mean its enough.
If you don't have an LS, I'd look for a gear oil without it.