I live in the Northeast and am debating on which weight of fluid to purchase for my manual transmission. MTL seems better for colder weather because of its lower weight, at different temperatures, than MT-90. Also, how does Redline compare to Amsoil gear fluids? What is everyones opinion on the particular brand and type of fluid to buy if I live in the Northeast?

 

I have similar questions as you & interested in the pros/cons of MTL and MT-90 in climates that range from hot summers to cold winters.

I've read a few posts that say MT-90 is the best match to Nissan's recommended M/T tranny fluid viscosity. I've also tried to compare data on Red Line's and Amsoil's website but with little luck. Part of the reason is that the viscosity numbers are pegged against different temperatures so we can't compare "apples to apples".

That said, I put MTL in my car (only because I wasn't able to find MT-90 around here in Toronto). I can say the shifts were really smooth in the winter months (& it was often really cold especially with the wind chill factor). Now I'm curious if the lower weight of MTL will adequately protect the tranny in the hot summer months.

My 0.02

 

MT-90 is what you should use. It matches the specs in the manual. MTL might be ok, but it's viscosity is out of spec. I'm in CT and have used MT-90 for over 80,000 miles.... Buy it over the internet if you can't find it locally...

-RMB