Yesterday I just bought what looked to be a really well maintained '08 MR TC-SST with 36k miles from a dealership in Port Charlotte FL that had mods and tunes done there by previous owner. CAI, Perrin Intercooler, Custom FM trans cooler, ceramic coated and wrapped exhaust manifold, test pipe, cat back, coilovers, seems to be running about 20lbs of boost at WOT (Defi boost gauge is telling me), Running about 10 air/fuel ratio at WOT. Manager was telling me they have a department that specializes in modding Nissan's...it's a Nissan dealership, and they took the car in from someone that was a former employee and that all the work had been done at their place. Test drove it, never a hint of issues. Told them the only thing I was concerned about was the trans and clutch, they agreed to personally warranty the items for the remainder of the factory warranty, which they told me was for 7 more months. Take it home, no issues. Driving home from work today I was merging into traffic after paddle shifting down into 4th, and under power transmission disengaged. Had to pull over, and turn off the car in order for it to go again. Transmission was shifting hard, especially downshifting from 2nd to 1st at a stop light, until I could pull over again and turn the car off. Was seriously spooked, drove very conservatively home, sick to my stomach that I just bought a car with a bad trans. Tried to call dealer, but they had already closed. Anyone have any info. I'm a professional father of three, and did not have much time today to find more out. I think it was more than the trans going into limp mode. Opinions? Just trying to get as much info together before I call the dealer tomorrow.

 

I can't sleep because Im a bit worried about getting this taken care of. Wanted to correct that it's tuned to 26-28 psi. Went out for a ride after my first post to see if it would shift through gears ok. It did, but it dissengaged one time with a 4th gear roll on. Seems to happen when trans is taken out of auto mode. I shut it off, trans reselt in about 1 min, and it drove fine from then on. Just venting because Im stressed out, and cant call the dealer 'till morning, lol. I'm very mechanically inclined, grew up working on dirt bike and snowmobile motors, work on my own cars, have done things up to changing headgaskets and the like. I just dont know enough about this car. Bought the car thinking it could be a daily driver.

 

The SST transmission has an overboost function that forces the clutches to open up if it detects 30psi of boost... maybe this is what is happening?

 

https://www.evolutionm.net/forums/ev...off-fixed.html

 

If this is your issue, and since the car is your DD, you may want to get a boost controller and have your car tuned for lower psi. Maybe 25-26?

 

I bet you that's why the employee traded it in... Now keep in mind with X's you don't necessarily need a manual boost controller, get a 3 port boost solenoid and and the tuner can correct this overboosting issue, it is very possible you are just spiking past 30.

 

Took it in Friday, and it only happens when in 4th gear in manual mode, and will disengage at about 70 when held WOT in a 4th gear roll on. I was watching boost and gauge was showing about 26psi. Not sure how fast/accurate they are, but that's far from 30. Im on vacation out of state this week, and they said it will be resolved early this week. It does not have a three port solenoid on it.