It used to be whale oil, but they changed it!
Yea, old timers think the whale oil is the only good stuff. Pretty shameful that they ever used that. It might be old man's tales.
Someday you will be an old F**rt too!
There is a branch of chemistry called LIPIDS, with a subbranch called, marine-oil triglycerides
. You might want to Google it.
The marine oil extracted for lubricants was Whale oil (which we have discussed here a least 12 times in this forum alone), or more accurately, Sperm Whale oil, from the spermiceli organ and which contains mostly liquid wax esters and some triglycerides.
This liquid Wax ester was primarily used in ATF fluids as friction modifiers because they were what was needed at the time and had quite good oxidation resistance.
Today, the liquid wax esters are synthesized by reacting euricic acid or other comparable acid(s) with specialized alcohols.
The euricic acid is derived by the fractioning of rapeseed feedstock oils.
I pity those poor rapeseed plants for having to endure this victimization.
I am sure the Gaiaon's would not approve of this process as well.
I don't use limited slip additive. Why reduce the effectiveness of the system? I want it to grab hard when the right wheel starts to spin. Clutch popping sounds cool. Back end getting twitchy is also cool.
With your comprehensive mechanical background, I am sure you are aware of something called, "stick-slip," which is not to be confused with "slap-stick" comedy.
This a sudden jump in relative sliding velocities which can cause excessive wear in Limited Slip Differential clutching mechanisms.
LSD additives reduce or eliminate the "stick-slip" action in order to reduce mechanism wear.
I always recommend adding 1/4 of a tube increments of LSD FM additive to the differential lube, and then testing doing figure eights to determine if stick-slip has been reduced or has disappeared.
I.E., use only enough LSD FM to make the stick-slip vanish.