Just how bad are the MR 6-Speed Transmissions?
 

Hey guys. I used to always remember reading here & there about 6speed issues, primarily with 3/4th gears.

What is the deal with these trannies? Are they ok for bigger power? I am looking to make 420-500awhp with my next Evo, and keep finding insane good deals on these MR's. Just wondering if I should go that direction, especially since they have the BBS wheels I want from the get-go.

Oh, and also, do you have to shift to 5th in the 1/4 mile with that kind of power? With 120-130mph trap speeds, im sure. Thanks guys.

you should be fine with 420-500whp. i say 500 would be max and pushing it a bit if your not planning on building the transmission. It also depends on how often your are going to track it. Overall, I i think the tranny is fine as long as you dont abuse like crazy. May I ask what are some of the insane good deals you have found?

One particular GG MR here on evom is going for 22-23k. Lower mileage too. Found quite a few under 25k, but having a more difficult time finding a GSR under 25k.

Out of the 10 months I owned my evo8, I never once tracked it. Just moreso did a bunch of highway pulls, thats my favorite.

I have the same question. I hear its ok for how ever much power you want then i hear it will only hold about 450ish so idk. I really want a 6sp tranny, a lil better on gas i think. Also im just use to it lol.

From the threads I have read here, the failures are usually due to heat generated fatigue, much more common with road race and autox situations where the heat is generated over long periods of time without the chance to dissipate. Drags and highway pulls dont put the thermal stress on the weaker gears like a raod race situation. Some six speeds have suffered failures with 350whp cars on road courses while drag cars with 500whp have made multiple passes without a problem. The failure depends on the situation.

Yeah I feel the same way about the 6 speeds. I've in no way been nice to my 6 speed tranny. 30k miles in ONE year and spent a lot of those miles banging gears and no problems yet knock on wood. Also started doing no lift shifting which I heard puts a lot of stress on the tranny for about 3k miles.

If something does happen I might just drop a built shep 5 speed in there though. {thumbup}

Six speed is really more stout than people give it credit for. 4th gear is the one that usually fails due to it being thinner than the 5 spd. to fit all the gears in their box. This has always occured at the track (road course) though during multiple hot laps. I have read a lot on this subject. Mainly after purchasing my second evo (ix MR). After reading countless posts it has pretty much been determined that the 6 spd. is just fine for autox, drag, and street driving. I have even heard gears 1-3 are more robust than the 5 spd. Even light track duty. Of all the failures I have read about all the trannys were heavly tracked, heavly abused, or trying to hold 500hp or more. In most cases it seems the 5 spd. would have prob. failed too. With the evo being on its tenth version and mitsu having so many years of r&d invested in this car, its hard to believe they would sell it with a tranny made of glass. Any part is gonna break if you beat on it too much. Yes the 6 spd. may not bet quite as stout as the 5 but it is my opinion that it can survive what 95% of evo drivers would use it for.

I haven't had a problem, but then again I dont abuse the car..

The weaker gears are the 5th and 6th which are thinner and smaller. It does take heat to damage them but autox is 1st and 2nd, maxing out at about 60-70 second runs. No way that hurts. Prolonged 20 minute road race sessions at high speed are what kills the top gears, especially if you start banging them.

NLTS is also not a good thing on any tranny, clutch or axles. I wouldnt do it to my MR.

BTW my MR is an 05 with 39K on original stock clutch. Shifts smoothly and doesnt crunch even 1-2 shifts. HAs about 20 autox over the past 2 years. I use Mitsu 6 spd specific Diaqueen in the tranny. Not even any hint of metal shavings. I do hold the launches to 4000 and slip the clutch a little to help the launch. BTW the clutch doesnt slip at all.

Milburn

I have an 06 MR with 30k and i have no problems shifts like butter.
I couldn't have made a better decision.

Not bad at all. I actually prefer the MR transmission, if mine ever fails I'll have it rebuilt, no plans on switching to the five speed. People that drive my car always comment on how smooth the transmission is. I never worry about the MR transmission being weak. I always put OEM fluid in and it always shifts like butter. I also have 30k miles on my car.

Lets say you do need a 6 spd rebuild. Since its mentioned that the gears are smaller to fit, is it the same bell housing as the 5 speed? Im basically asking, because if the 6 spd does fail, can Shep convert it to a 5 speed?

Good luck selling your car one day after somebody does a post search on you lol

i talked to shep trans a while ago about that. they said you need the 5 speed case. they are different

Like others have stated, just take care of it and it will take care of you. Just make sure you do the Normal Maintenance and by not excessively abusing it, it should be fine. Some have better luck than others but for the most part, I'm sure there are plenty of people out there that have no problems with it.