Hi , i’m about to change my transmission and diff oil and a friend says; go for 75W-140 for BOTH??? He pretends it’s competition stuff and it handles higer temperatures very well but…..1. I am not racing the car just some occasional fast road and 2. I never heared you can use one oil for gearbox and diff? Almost forgot; the car is a NC 2.0 2010.
No just use 75w/90 for both or what’s recommended.