TRE recommends using the following manual transmission oils listed below for use in your Mitsubishi manual transmissions including the EVO-X manual transmissions. We critically question the validity of Mitsubishi's recommendation of a GL-3 oil specification for the EVO-X manual transmissions as this oil clearly lacks the proper EP additives to keep the center differential spider gears from seizing to the cross shafts and shearing the
retaining pins. Listed below are a few of the gear oils on the market for you to choose from.
MOTUL GEAR 300 75W90.
This oil has incredible film strength while still allowing for quick shifts making it another wise choice of oil for your high power Mitsubishi transmission. Scott Evans likes this oil and so does TRE. Part# 100118. Note: We are talking about GEAR 300, not Gear 300LS which is a full GL-5 gear oil and has the friction modifiers that are required by limited slip differentials.
This gear oil offers improved shift quality in most manual transmissions and would be fine for stock power levels. Part# 50304
This synchro friendly GL-5 rated "no-slip" gear oil provides improved film strength, reducing the scuffing that we commonly see in modified vehicles that that are making more power than stock, while still offering good shift quality. Part# 58304.
NS GL-5 Gear Oil.
This is an excellent gear oil that will
keep the gears and bearings from frosting or scuffing
in a high torque application. It's one of the best oils that
we know when it comes to gear protection in those mission impossible applications but keep in mind that it may be too slippery
for the synchros to work effectively at high rpm shifting. Part# 57104.
AMSOIL Manual Transmission & Transaxle Gear Lube 75W-90 (MTG). This API GL-4 rated gear oil has good stability and film strength and would be fine for near "stock power" levels. Part# MTGQT-EA
MITSUBISHI DIAQUEEN SUPER MULTI GEAR OIL. This oil is rated 75w-85 API GL-4 and we recommend that you
use it if you can't find the other oils that we recommend. Part# MZ313376.
FRICTION MODIFIERS. Never add a friction modifier to your transmission gear oil as it will make for poor shift quality. Understand that the friction modifier is an additive that reduces friction and is designed to reduce noise that limited slip differentials can make while making tight turns at low speeds. Do not use it in your transmission.
There are concerns about using REDLINE SHOCKPROOF type gear oils inside manual
transmissions. While this is truly an excellent product, it has
been found that the heavy Teflon-like particles are
quickly centrifuged out of the oil and will build up inside the
center diff housing and around the synchronizers and
inside of the gearshafts. After several oil changes this
may block oiling passages inside the gearshafts. Also this oil is has too high of a viscosity for
winter use. Therefore we cannot recommend using SHOCKPROOF in
the transmission unless the transmission is to be serviced
often or a dog box.
Remember that proper viscosity is important when it comes
to splash type lubrication; certain parts require enough
viscosity so that the oil will get thrown far enough in
the proper direct to provide lubrication so please
check out the viscosity chart and choose an oil for the
operation temperatures of your transmission. Ideal transmissions temps should be between 140-200 depending on what you're doing.
Oil must be level with or slowly flow back out of fill/level plug. It would be wise to drive the vehicle a short distance and recheck the oil level and top off as required. Road racing & drag race applications
may add an additional pint of oil to the transmission for
added lubrication and cooling.
EVOLUTION OWNERS TAKE NOTE:
It is of utmost importance that the transmission oil be
checked again after driving the vehicle due to the oiling circuit for the front
differential. You must to drive the car a few miles at
speeds over 25mph to fill the front differential housing
and then top of the transmission oil level. Driving the
EVO with the transmission oil level too low will shorten
the service life of the 3rd & 4th gear synchros.
CHANGING THE OIL:
Vehicles that are being road raced require race car
maintenance and all drivetrain oils should be inspected
after each race and preferably changed. New or
recently rebuilt transmissions should have the oil changed
after the initial first 500 miles and again after 1000
miles, then every 5000 miles. Contact TRE if you have questions about using a cheaper break-in oil.