Review on 🔧 Genuine GM 24225825 Pressure Control Solenoid Valve for Automatic Transmission - Authentic OEM Part by Albert Lee

I believe this is the main reason for the "Maximum Long Shift Adaptation" code found in 4T65E transmissions. If the shifts are soft and sluggish and after a while the shifts become harsh with this code, I would remove that side cover from the transmission and replace the thing. If you are installing a used transmission, replace that part before installing it on your vehicle. This has been a problem with these transmissions for years and they redesigned this part a bit in 2003 but experience says this part has never been improved. It only needs to be changed every 100,000.