amsoil lists 2 different 75w-90 diff oils available for my '98 rnr(differential-front).. One is for diff w/ADRD and one shoes the fluid is w/o...i was thinkin this is referring to a locker but not sure. 4runner.org did not say he used one or the other.

thanks for the repsonses in advance!

 

Usually the additive oils are for use with clutch-type limited slip (positraction) typy diffs. Usually an open diffs or automatic/manual lockers are fine with plain old GL-5 gear oils. The friction modifiers are needed for the limited slip clutch packs to engage smoothly. The additives usually do not hurt an open diff, in fact you would notice no difference between the two types of oil. You could probably contact the Amsoil tech support folks for a vehicle-specific recommendation.

 

amsoil got back to me..ADRD is automatic disconnecting differential. They recommend the 75w-90 severe gear for either one.