Hello everyone. The owners manual of my Nissan says to use OEM Nissan 75W-85 GL-4 gear lube. Well that stuff is $20 a quart from the dealer. Yes it is cheaper online but when you add S&H it is still $20 a quart. Redline makes MT85 at $17 a quart. Amsoil makes an MTF 75W-90 for $11 a quart. I talked with Amsoil and their tech said NO they do not make a fluid for my car because the viscosity is not the OEM spec so they will not suggest that I use it. In the real world, is there a big difference between a 75W-85 and a 75W-90 with a GL-4 spec? In my mind I feel the Amsoil would be a better product than whoever is packaging the fluids for Nissan. The Amsoil is also much cheaper. I would like your thoughts on this.