So yet again I have another issue thats freaking me out, this time with the twin clutch tranny. It started a few days ago after I put my stock cat back on from a test pipe. I'd be driving normally and when it would shift in auto mode, it would a "rough shift" I guess could explain it. Like when its shifting the tranny will shake and makes the car shake backward and forward. It's slowly been getting worse and tonight on my way home from work, that was happening PLUS...now I was driving and when I came to a red light or had to slow down for a turn, the sst wouldn't downshift. I was at like 10-15mph and I was still in 6th, when normally it downshifts as I slow down. So after a 8 second delay, it would jump down to like 2nd and once again the tranny would shake like crazy which made my whole car shake, and I couldn't accelerate since it was in 6th gear at 15mph and was a safety issue and bascially scared me. Anyone know what it could be? Or am I better off putting my car to stock and service it? I'm afraid to drive my car, don't want the tranny to break now...

I tried to search but couldnt find anything and typed in my problem and found no threads.

 

Bump, anyone?

 

What mode/modes (does it happen in normal/S/SS), how do you normally drive it? Mileage? SST fluid/filter ever changed? Mods? Tuned?

If not modded (although either way really), take it to the dealer and get it diagnosed ... warranty is the way to go if you are able

 

It happens only in auto mode, mainly in normal. I tried in sport and it downshifts normally but upshifting feels funny still. Normal mode is the main trouble. When I drive manually it feels perfectly fine. I'm thinking its a computer thing, like the ecu. I have cobb stage 1, cobb intake, ultimate racing catback with stock cat, that's it performance wise. I used to have a test pipe on and put my cat back and the problems happened after the cat went back on. Any possibility if it as to do with the ecu relearning with the stock cat and stuff? Idk if the ecu and tranny has anything do with it.

 

I'm at 13000 miles, I haven't had any tranny fluid change, I bought the car used with 8k miles.

 

First check for vacume / boost leaks as they can change the load the ecu sees and thus affect the shift pattern of the sst in auto mode.

Next, reset the ecu... (pull the battery negative cable and let it sit for 30 minutes or so), you never know the tcu may do some learning, but probably not a whole lot.

After that I consider a sst fluid and filter change.

 

I reseted the ecu. The shifts seemed to be normal, but the downshifting is still messed up it seems. When i'm braking to slow down it still seems to have a delay to be downshifting. Cause in normal mode as you slow down it'll just downshift. Sometimes as I'm slowing down, it'll actually upshift then downshift as I'm slowing down, which is weird. It hasn't done the "scary" thing like last night when I was slowing down on a main road and it wouldn't downshift for me to accelerate as the light turned green. It stayed at 6th gear as I hit 15mph and i tried to gas it then it dropped to 2nd in a split second. I'm hoping that problem won't happen again.

I don't see how fluid change would help. Problems like that or new clutches type stuff would be if in any mode the gearing would be weird, but in sports mode and manual mode seems to drive fine.

 

So in sport auto it down shifts fine? I would think if it were engine load reading related, it would act funny in sport auto mode as well.

Have a look at this: https://www.evolutionm.net/forums/9325332-post1838.html

Seems like the inputs are vehicle speed and tps, I would assume load as well. In short if it only acts strange in normal mode then a trip to the dealer is in your future You might try getting a datalog of tps, app, load, and speed when it acts up and see if there may be anything in the data to point to the issue.

 

Yeah it's just normal mode where I notice it acting weird. Was worse this morning going to work, idk if "cold" start makes it worse. I just figured I could find an explanation on forums vs a dealership since they don't sh*t half the time here in San antonio

 

I am also experiencing what the OP is (mainly the weird downshifting issue going from 6th to 2nd in a split second) but also sometimes it does that weird upshift thing when slowing down before a downshift. All this only happens in Normal mode as the OP also said. I also got a service engine soon light one day on the highway, but oddly there was no code when I tried to read it so I just reset the ecu and it hasn't come back since. It's been about a week now.

I recently got my car checked out by my tuner and everything looks to be running normal. The car has an AMS downpipe, AMS high flow cat, Borla cat back, K&N intake with UICP.

I got my car checked for boost leaks and I'm all good. So personally I'm thinking it can be only two things. Either we are due for our tranny fluid/filter...personally I doubt I'm due since I'm at 19k miles and the manual says 30k for the change. Or the Cobb AP maps need some adjustments for SST users. By the way I'm on a 93 octane stage 2 map protuned.