05/10/2026
We frequently get asked about what we rate certain trans builds at, and that is not something we really do. It often puts us at odds with customers, as everyone wants a simple yes/no answer, and it is not that simple.
But to help out, I'll put it out there as simple as possible on what to expect from a Mitsubishi W5M33 transmission. This is data I've collected over 20 years of watching others, and my own results.
For ANY OEM Mitsubishi W5M33 gear set, 90, 91-92, 92+, EvoIII, ect, assuming new or gently used gears with no built up fatigue, and good cases/bearings, the lifetime due to gear tooth breakage can be summarized by:
At 250-300ft*lbs expect it to live almost forever. The gear teeth should last 100 million+ cycles, or revolutions.
At 500ft*lbs, expect it to last around 100 passes.
At 700ft*lbs, a few passes.
At 1000ft*lbs, instant failure.
There are modifiers of course. Shotpeen, cyro, ect can give you a fractional increase in life. 100 passes might turn into 125.
It can go the other way. Buy a used OG gold standard shep stage 4. PO had it in a 700ft*lbs setup for a few hits. That used up 50-75% of it's life and now it only lasts 25 passes at 500ft*lbs.
Put a 1000ft*lb clutch in the car even though your engine makes 500ft*lbs and you still hit the trans with 1000ft*lbs every launch or NLTS. Now it lasts 30 passes instead of the 100 it could have.
These guidelines go for any of these transmissions, weather it's a be**er junkyard pull, or the finest work from me or TRE or TMZ ect. At 300ft*lbs life is almost infinite, and at 1000ft*lbs it is instant failure. Extrapolate from there based on prior use, and other modifiers.
There is nothing you can do in these transmissions that would make a factory gearset live and infinite life at elevated torque numbers. You might just get a fractional increase in the number of passes it lasts before failure.
Even the all-mighty ppg dogbox lives by these rules, the torque numbers are just moved up a bunch. Probably something like 500ft*lbs is infinite life and a few passes at 1500ft*lbs, and then instant failure at 2000ft*lbs. The are strong enough us normal guys will probably never break one, but the guys chaising 7's and beyond break them regularly.
