Zaxz28

2000 camaro issue with transmission seems to shift fine a little different after I got 3.73 in it I have put about 2000 miles on the car since I got it tuned and gear change set for the computer done by "The Man" Frost. Just had P0751 code come up I have done the research...
Things I have done to or around the transmission:

Had the fluid changed 10000 miles or 2 years ago.

put in a temp sensor in the tranny case where the pressure port was about 4 months ago.

Just checked the pcm plugs after my tune and they were a little loose.

What is the worst case scenario, do you have to pull the transmission to replace that solenoid, what should I try before I resort to replacing the solenoid..

Update: pulled the negative cable to erase the code tightened the pcm plugs, took it for a drive, payed attention to the shifting, seemed to shift just fine light and under heavy load, No code came on.
Can anybody tell me how the car would drive and shift if solenoid valve A went out?

Thank you guys I know it is the forth but any help other wise this could ruin my 4th of July