This is for front/rear differential for 2000 ml55 amg mercede. Can I use Amsoil 80w90 for front and rear or get 75w90 Amsoil? I know Motul gear 300 is 75w85 is good for rear. But idk. I believe front called for: 85w90 And Rear: 75w85 I'm having hard time choosing what brand of fluids should I go with. Money is not the issue since I only needed total of 3 qts for F/R.