DSM / 3S / EVO Transmissions 2.5 - 3 Quarts
DSM / 3S / EVO T-Case: 1 Quart (just short of 1 quart)
DSM / 3S / EVO Rear Diff: 1 Quart (just short of 1 quart)
V160: 2.5 Quarts
SST: 8-10 Liters (depending on pan size and/or external coolers)
AZ6: 2 Quarts (1.75L)
Focus RS: 2 Liters
GR6: 10-11 Liters (depending on pan size and/or external coolers)
GTR Rear Diff: 1.55 Quarts
GTR Front Diff: 0.65 Quarts


For our EVO / DSM / 3S / AZ6 / V160 Transmission rebuilds we recommend OEM Mitsubishi transmission oil, Motul 75W90 (GL-4/5), or Redline MT90 (GL-4). Gear oil choice is very important and varies based on preloads and synchro blocker ring design. It is strongly recommended that you stick with these fluids for our built transmissions. Contact us if you are unable to source them locally. We stock a variety of approved oils and fluids. Please note: The Redline MT90 may feel a bit notchy when used in colder climates. Once the fluid warms up, it should be smooth. 
Our fluids and filter section can be found on our website here

The Focus RS, TC-SST, and GR6 transmissions all require a quality Dual Clutch Transmission (DCT) Fluid.


DSM / 3S: 

  • Use Redline Lightweight Shockproof in Transfer Case and Rear Differential. DSM: If you have an EVOIII rear diff, do NOT use Shockproof as the LSD will not work with it. In these applications, we would recommend you use Mitsubishi LSD oil.

EVO 8-10: 

  • For an ACD T-Case, the recommended fluid is the Mitsubishi LSD gear oil. If you have a Non-ACD T-Case, we highly recommend using Redline ShockProof Heavyweight (Red). 
  • For the rear diff, we recommend the factory Mitsubishi LSD oil as the clutch packs for the limited-slip will no longer work correctly if you use Shockproof.


  • Use OEM or Motul 75W140 Gear Oil in the front/rear differentials


DO NOT use Synchromesh, BG Synchroshift I or II, Royal Purple, or any other unapproved transmission fluid. Those fluids will destroy synchros / gears and will void your warranty! Absolutely DO NOT use Redline Shockproof in your transmission!   

Shockproof is designed for ring and pinions found in T-Cases and Rear Diffs. If you use it in your transmission, you will break gears and ruin your synchros!

The pic below is of an EVOIII 1st gear which only had 6 months of use with Shockproof oil.  Shockproof causes odd gear failures like this one where 1 tooth in your 1st or 2nd gear will end up breaking off and missing.  We have seen a bad rash of odd failures like this with Shockproof users.


Shockproof can also cause fretting with gear teeth in your trans.  Here is a picture of an EVO 9 1st gear and input shaft after using Shockproof:


How that customers gear didn't break is amazing!  

Shockproof also has no friction modifiers, which means that synchros will be unable to work correctly and will have to work serious over-time in order to synchronize your trans correctly.  Synchros need friction in order to properly operate.  When there is no friction, they are under a large amount of pressure and will wear out very quickly.  They will also feel notchy and unpleasant to shift.  

The wax found in Shockproof oils will also plug up your small oil passages found in the synchros, shafts and center diff in your trans.  Just please don't use it!

Shockproof oils are an unbelievable achievement in engineering and a miracle oil, but only if used as intended.  Use Shockproof in your T-Case and you will never have to worry about worn ring and pinions again.  Use it in your trans, and you'd be lucky to get 6 months out of it.  It is clearly stated on Redlines instructions to NOT use Shockproof in your trans.  Take their word for it, they are the people who engineered it and know best.

Take our word for it, use the factory Mitsubishi oil or our approved oils in your trans at any HP level!  We don't see gear failures like this when people stick to our recommended fluids. Yes, we know, many people believe that you must use the most overpriced aftermarket oil for your trans, if you are to push a lot of power through it. The fluids we offer and recommend are pretty amazing and will give you the cleanest gear wear along with the smooth shift possible. 

Next question we always get is: Can I use a mix of Shockproof or some other aftermarket oils with the factory fluid?  The answer is NO!  Please get away from the mentality that you must have some kind of aftermarket fluid in your trans!  Use 100% Mits fluid mixed with nothing but more 100% Mits fluid.  It works great as it is and will give you the best life and performance possible. 

We don't know who has been starting the rash of Shockproof in your trans or mixed with other fluids as a good thing, because it's not.  Please don't do it!

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3920 North Weber Street Colorado Springs, CO, 80907

Hours: Mon-Fri 8:30AM-7PM MT


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