Oh buddy it does contain friction modifier, the entire base oil are esters. This is why you made a perfect choice for gear oil. Mineral oil needs modifiers, Redline's base is the modifier. I recommend NS for this very reason, you choose the right oil. Still a very low chance you need them, but better to wait to see if you need them. Most people do not, still have not heard of anyone here needing to add it.
If you see a ZDDP replacement is what they use in all of those anti slip additives, if by chance you do need it, that will smooth out any chatter. So on a scale from one to three, three being the most aggressive in the gears, zddp replacement is the strongest at friction/anti friction balance, esters would be number two, and mineral oil would be number one. Mineral oil almost always needs it added. It is also widely excepted too much anti slip is a bad thing as well, so you want to be as least aggressive as you can but still have smooth operation. This is also why you only add one ounce at a time to smooth out chatter, they don't want you to add the entire bottle. Nobody really knows what zddp replacement is, something chemical maybe different in every brand, but made to serve that function. The second half of that link explains it, those metal salts and other such things they list are possible anti slip additives. Don't worry, you wont need it, just posted to inform.
from link
Esters, natural and synthetic fatty acids as well as some solid materials such as graphite and molybdenum disulfide are used for these purposes.
Side note, why not just use mineral oil with the strongest additive? There are many other benefits from esters in gears such as they don't break down with heat, lower heat in operation, and naturally keep them clean, and triple and then some the oil change interval because they don't break down.
Secondly, it is a balance, so when you go with the strongest first, you are potentially tipping the balance. Now, in consumer gears, it likely really doesn't matter. But if you really had load on those gears and you didn't have the right balance either way, those gears fail. Millions of people use mineral oil with additive and it serves them well, it isn't a bad strategy in consumer gears. I still like the ester based stuff, in case I get lazy and don't swap out the fluid when I am supposed too, I know I am still covered. But folks will have real good protection using stuff like M1 gear oil with anti slip additive, I'm not saying different.
I am not sure about the gear fluids that have the anti slip already in, what happens if there is too much in there? I don't really like that personally. If most of the after market anti sip additives say only add one ounce at a time and no more to smooth out chatter, how can oil companies get the right amount of anti slip in their formula? Seams like they would error on putting more in to smooth out chatter then worry more about the balance. Redline NS gear fluid seams like the perfect choice imo, nailed the balance.
