I have TOO MANY opinions and need a real answer.

I want to do what the ownes manual says but i don't know anymore and my brain has melted. Any help or comments would be nice.

 

Transmission = GL4 SAE90 (or 75W-90)
Transfer case = GL5 SAE90 (or 75W-90)
Rear Diff = GL5 SAE 90 (or 75W-90)

 

Don't forget Redline MT-90, for me it has been pure transmission magic.

 

Redline MT90 = GL4 75W-90 synthetic

 

Do not use a GL-5 oil in the transmission.

 

I heard the redline stuff was bad for the brass parts in our transmission. Errosion is almost continuous. That's probably and overstatement, but I see what they're getting at. Additives are also a big no-no on the brass parts.

This one is supposed to protect the important brass parts in our transmission very well:

"Castrol TAF-X 75W-90 GL-4 gear oil is made in the U.K. and sold
only in Europe. However, the equivalent in the U.S. is Syntorq LT.
Having said that, Syntorq LT SAE 75W-85, API GL -4 is a premium high
performance, synthetic gear lubricant for synchronized manual
transmissions. The all new "clean slate" approach enables Syntorq LT
to provide consistent performance and durability under the most
severe operating conditions due to its unique polymer free formula.
It has been designed primarily as a problem solving gear lubricant
for manual transmissions to provide reduced gearshift effort at low
temperatures. Syntorq LT is available through General Motors (Part
#12346190) and Chrysler (Part #4637579) dealerships. Please contact
your local dealership."

In Europe, this is mainly used in motorsports. Lotus, Porsche, BMW, Jaguar, and Honda all use this in Europe.

 

This is from the Redline tech info pages:
MT90 is hard to beat - I've raced the crap out of my Celica's 6sp (road track), and it performed absolutely flawless.

 

Redline MT-90 is really the only Redline product you should run and it goes in the transmission.

The other Redline products (75W90, etc) are not suitable for the transmission because you need GL-4 and are not suitable for the transfer case or rear end because they are too thin.

So for the transfer case and rear end I recommend Royal Purple SAE90 (stock like fluid but "better") or just the stock SAE90.

 

Go to your Mitsu dealer and ask for a couple bottles of the GM Syncroshift [Syncromesh] (yes, the Chevy stuff) they have hiding on the back shelf (Mitsu service fix for "notchy" transmissions). It is cheaper to go to the parts store and get the non synthetic Pennzoil Syncroshift however. If you want the actual part numbers, do a search for the long assed threads on the topic. Basically it was found that the GM, BG, Pennzoil Syncroshift is all made by Pennzoil, and seems to shift the smoothest for those who have tried all three However, it seems to like to be changed more often.

I'm using RL Light weight Shock Proof in the xfer case/rear diff. However that is a personal preference for someone who doesn't drag race at all.

 

what about royal purple oils ?

 

good thread guys. I read on a few posts that the Pennzoil was to thin for our trannies. Can anyone clear this rumor up?

 

So far everyone is in agreement and that helps a lot.


Transmission = GL4 SAE90 (or 75W-90)
Transfer case = GL5 SAE90 (or 75W-90)
Rear Diff = GL5 SAE 90 (or 75W-90)

 

NOT (or 75W90). Keep that weight OUT of ALL of your Evo. Stay with full weight 90 in your diffs. When it is flowing at 75 it is too thin.

 

Follow the FSM's recommended gear oil weights and you shouldn't have to worry about anything.

Personally, I'm using MT90 in my tranny and stock fluid in the t-case and rear diff.

 

According to the FSM, this is what the above should be:

Transmission = GL4 75W-85 or 75W-90
Transfer case = GL5 SAE 90 ONLY
Rear Diff = GL5 SAE 90, 85W-90, or 80W-90

BTW, Pennzoil synchromesh is SAE 80. I'm thinking about mixing it with some MT90 on my next oil change.