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5-speed gear oil

15936 Views 17 Replies 13 Participants Last post by  fitfors2k
Has anyone used amsoil 75w90 gear oil in the 5-speed tranny? What is
different or special about Honda manual transmission oil? :D I understand the amsoil gear oil increases fuel mileage.
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For the syncros in the manual transmission to work properly, a certain amount of friction additives is required. Synthetic gear oil is designed to minimize friction as much as possible for gears and it is much more successful at that then petroleum based gear oils.
Using the fantasticly slippery amsoil gear oil will wear out your syncros because they will slip much more instead of engaging quickly. It's best to use Honda's own manual transmission oil.

I've inquired with the hardcore racers at HADA club (honda acura drivers assosiation) about transmission oils. Most have tried specialty synthetic transmission oils like Redline, Motual etc.. and even fords heavy duty transmission oil. The conclusion is that almost all of them have found that the Honda trasmissions work best with the Honda transmissions.

Keep in mind that all these guys use synthetic engine oil because there is no question that it's significatly better then petroleum engine oils including honda's own.
Redline MT-90 fluid is very good, and they work fantasticly in Subarus etc..
The Redline MTL oil is designed for transmissions like the Hondas so it will work well, and maybe improve mileage slightly in winter.
But the honda racers I spoke with said the honda transmissions shift better and faster with the Honda MT fluid then with Redline MTL.

YOu can try it, it will do no harm.
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