Codes p700 + 2821 2.0L Premier suddenly

[Wilsongone]

Hello and sorry to jump right in. My 2018 Equinox Premier 2.0L T FWD has failed with all lights (CEL, Stabilitrack, etc) is in Limp mode. Onstar reports 3 codes P300 (General misfire) P700 (TCM) and P2821 (Pressure control solenoid stuck on). Car runs super rough, but seems to shift (although it acts like in limp mode). I dropped it at the dealer...(stealer) ...and they want.....hold on you your seats....$10,500 to fix this issue. I am more than a little concerned that this is just way out of line? Perhaps I can just change the pressure solenoid and it might be OK? Or do we really think this car is toast?
I am of the opinion that perhaps I just change the solenoid and clear the codes and off we go, but this thing does have 225K on it, so ?
Any advice?

 

[Big Papi]

What were they proposing as a repair? Keep in mind a dealerships business model does not allow for extensive diagnosis but geared more to fast turnaround and profit. Go get a second opinion.

 

[Wilsongone]

What were they proposing as a repair? Keep in mind a dealerships business model does not allow for extensive diagnosis but geared more to fast turnaround and profit. Go get a second opinion.

Indeed this seems to be a case of not looking too deeply on the dealership dime. They want to purchase a complete new trans. I think I understand why, but this seems overkill for the symptoms?

 

[Lee]

Ask if Pressure control solenoid stuck on is related to the vacuum pump. Did the brakes require more than normal pressure?
When the vacuum pump goes it can destroy the head or complete engine.

 

[Wilsongone]

I have had it towed home. I will take it apart and get to the bottom of the failure without incurred labor cost. I will post what I find.