Does anyone know if you can add gearbox Slik 50 to the rear dif & gearbox and center diff on a jap import WRX, it's just that as I understand there is a limited slip diff in the rear and a viscous type LS in the center diff, I have read that the rear diff is a mechanical type LS, will the Slik impair there operation. I have always been a great fan of Slik for both engine & gearbox but I know from my rallying days in a MK II Escort which had a clutch type LSD you could not use Slik in the diff.

 

I wouldn't use it, Nulon do a similar product that is designed for limited slip diffs.

The gearbox should be fine. The one thing you need to be careful of is the hypoid gear, make sure that the tranny fluid and additives are recomended for Hypoid gears.