Im planning to run Amsoil 0w40 4 stoke in the motor and severe gear 75w140 in the chaincase. Is it relly gonna be worth it to spend more on the oil and shipping for the 75w90 for the diffs? Ive been running Valvoline synthetic 75w90 in my brother Gade 800 since we got it without issues and he beats it. We mud/creek ride a fair amount and the rest of the time were hill climbing so I change the diff fluid quite often when were in water. I wanting to run Rotella T6 in the motor because its walmart ready in a bind and cheaper but I had 2 Brute 750s that I absolutely abuse and ran amsoil in them with zero issues, Im a believer in Amsoil but also a believer in not spending more than is necessary. Id like to hear some input from the racers and builders on here. Summertime can reach 95 here and winter can be a few degrees below zero. Ive read every oil thread I can find on here but I cant find a good majority of peoples oil choices.