After 3000 miles of a notchy 1->2 gear shift, I decided to change out the factory tranny fluid and try some Amsoil MTG (GL-4 75W-90). I was hoping it would smooth out the 1->2 shift notchiness, but no such luck. It did somewhat smooth out the 2->3 shift which was only slightly notchy. If it doesn't get any better by the next oil change, I'll have to try something different.

Anyone have good experiences with switching to a non-OEM GL-4 tranny fluid in an Evo 6MT?

 

It is what I use and the shifting is pretty smooth for me. However, the oil needs to get a bit hot for "butter like shifting" I have found. Of course I am using poly shifter link bushings, base bushings, short shifter and a stillway engine dampener.

 

The tranny fluid has to get hotter and oil needs to thin out to get smoother shifts on the 6 speed from my experience. Some have been using Pennzoil Synchromesh in the 6 speed trannys for smoother shifts with great success although they do change it more frequently (3k miles)... Pennzoil and BG Synchroshift are the prefered tranny oil for the 5 speed.

 

Why not for the 6 speed?

 

Because of the weight and viscosity of the oil ...
5 speed uses 75W - 90 GL-4 and 6 speed uses 75W - 85 GL4

Pennzoil is GL-S rated ....

Personally I recommend using stock Diaqueen oils and driving carefully until the tranny fluid has had a chance to warm up.