How do you replace the transmission control solenoid on 2005 Pontiac Bonneville GXP?

To replace the transmission control solenoid on a 2005 Pontiac Bonneville GXP, first, disconnect the negative battery terminal and raise the vehicle safely on jack stands. Remove the transmission pan and filter to access the solenoid, then unplug the electrical connector and unbolt the solenoid from its mounting. Install the new solenoid, reassemble the transmission pan and filter, and reconnect the battery. Finally, check the Transmission Fluid level and ensure proper operation.