American Power

I need to swap out the old fluids from my track day at the glen. My oil temps went kind of high so I'm assuming that the gear oil and tranny fluid got baked as well.

The gear oil and trans fluid has a few track days on it.
I'm going the Royal Purple route, the gear oil has the friction modifier in it already.

Since I'm running the car harder than ever before with the Hoosiers, Coilovers and Stoptechs should I be using something thicker in the rear. Something like 75W-140, instead of the 75w-90?
Can a little thicker gear oil cause any harm?


I don't think so, But I would like to have some of your thouughts.

We run thicker oil in the engine at the track.

Gray Ghost GS

Redline 75W140 works fine. DTE recommends this fluid for their new differentials, which is what I received when I went with their 3.73 gears. It's what I plan to keep using - great for street and the track. BTW, great videos from Watkins Glen. Mike

John Shiels

If you are going to run the car hard a lot better tink of diff and tranny coolers.