Transmission Solutions
 

I know that some people have swapped in the T56, the 5 spd, and FD transmissions, as well as the gear-set from the Australian company. What I'm wondering about is what exactly fails in our transmissions in the 350~400 HP range? A friend of mine suspected it was the input shaft gear. Has anyone taken apart one that died from high horsepower and identified the weak points?

I'm trying to avoid a $6k gear-set if I can have a couple parts made at a local machine shop for less.

Mine spun teeth off 4th Gear going up a hill...

I wouldn't even try and fix a 6 speed...if you are going to play around go to the 5 speed RX-8 box or an FD box ( basically the same inside)

So far mine is holding up to 450 WHP road course. Drag launches and things will break for sure

Good times... so I'm hearing full gear set or swap. Thanks for the info.

The problem with trying to swap in gears sets is usually the strength of the case is an issue...often more of an issue than the gears.

My 6 speed trans never failed with 325whp going through it for 100,000kms . But I never did any drag launches or burnouts .
The rx8 5 speed trans I have now seems fine as well at closer to 400whp. The syncros fail on these from abuse more than from 400 plus whp.

I think if you are careful the 6 speed is good for 325 to 350

Mine died quickly with slicks at 450....

So far the 5 speed is working great.... I was thinking about going to a T56 based unit...but they really shift like a truck

Some people prefer the S2 6-speed MT both S1 MTs. I find this strange as over here in the UK the S2 6-speed MT is seen as relatively fragile; however, this may be because people are assuming there is a general issue from complaints over the inadequate 5th & 6th gear synchros on earlier R3s.

As an aside, over here in the UK there are plenty of the better-spec 5-speed transmissions to use in a turbo swap if/when the 6-speed transmission breaks. That, I suppose, is some consolation over the extra issues we have trying to plumb a turbo around out RHD steering column.