2008 MR with 62k miles on the dash with oem sst. only problems i had were related to timing chain, SST has been absolutely solid.

 

People worrying that this is a sign that the SST is going to explode if you mod it need to give their head a little shake.

There's always a chance something is going to let go, but proper maintenance on the SST will make sure it lasts a hell of a long time.

I'm at 60,000km with a full bolt ons, stock turbo with 0 issues - as with most people. There really are very few threads about the SST going **** up. MANY more threads about issues with stock clutch on a manual, gears feeling knotchy whatever.

It's a car, if you mod it **** may break. But it sounds like you got a lemon - new tranny is a good deal for you.

and 12k is way high. Jacks is a great deal or a used one for a couple grand and then rebuild.

I'm also pretty sure a 4.2k tranny from jacks is going to built - not stock.

 

I'm amazed Mitsubishi did the right thing.
IMO you had a bad unit from the start.
Good luck with the new trans, now no launch control for a while.
Joke.
New sst your all set

 

The OP stated that there car wasn't modded. My experience with Mitsu is they usually cover the issue under the warranty, although it may take a call to corporate. Had his Evo been modded then it wouldn't surprise me if they denied the repair.

My personal experience with Mitsu warranty on my Eclipse and posts like this, will keep my Evo completely stock until I am out of the warranty period.