Cusco 1.5 Type RS Rear Differential

[kyoo]

All,

Been struggling with this for a while, hoping to get some detailed, experienced input. I've got the Cusco 1.5way Type RS rear differential in the diff of my '06 Mitsubishi Evo. Uses include autocross, road racing, and getting to and from events (anywhere from 30 to 300 miles).

Recommendations I've seen include Cusco's 80w90 & 80w140 gear oil (hard to find), Mitsubishi's SAE90 gear oil, Redline 75w90, lightweight shockproof, heavyweight shockproof, on and on.

What I'm looking for is a good gear oil suited for my differential and my uses. Specifically, something that will protect well at my motorsports events, while flowing well and not creating too much drag.

As far as I can tell, Lightweight Shockproof sounded perfect - but people are saying because of the moly, it's not really suited for clutch pack differentials. Any suggestions would be greatly appreciated. This is semi-related to my thread on here about Diaqueen, but that's used in the t-case as well.

 

[RoadRaceJosh]

For a clutch LSD I would use the standard RedLine 75W-90, 75W-140 or 80W-140. I raced with a different brand clutch type LSD and found the 75W-90 worked great. If you desire different lock-up characteristics I would look at the NS stuff for more lock-up and the Shockproof for less. Even with the 80W-140 I expect you'd see no measurable increase in drag.

 

[RoadRaceJosh]

I take back my statement on the Shockproof oil. I would not use that. If you want less lock-up use more of the RedLine friction modifier.

 

[kyoo]

thanks for the input. leaning towards the regular 75w90 for the t-case and the rear diff