Toyota's call for 75w85 gl5 front and rear which is not common. 75w90 is though. I understand that interchanging those is fine but my question is in regards to paying extra for 75w90 syn over conventional. Is there any advantage? Does syn gear dope actually last longer and or protect better? I had strong opinions in the past but some Tacoma enthusiasts are trying to convince me otherwise Also T case calls for 75w...can I just run the gear dope?