Avenger - a lot of manual transmissions use ATF... Borg-Warners, for example. Al
s results would seem to indicate that lubes like MTL would also be good in the RS, but on Trey's site he discourages the use of MTL. Unknown as well is whether the ATF meets the GL-5 specs, or whether it is even necessary to have a GL-5 lube in the transmission. It is mystery to me why Al doesn't get massive grinding when hot, but apparently it works just fine. I dunno, there are some things we just don't understand. I am not alone in thinking that it's lunacy to put engine oil in the rear diff, though.