AW55-50SN Automatic Transmission Solenoid Set 8-Piece

This is a complete eight-piece solenoid set for the Aisin Warner AW55-50SN five-speed automatic and its close relatives, the AW55-51SN, AF23, AF33-5, AW235 and the Nissan-badged RE5F22A. It is the transaxle under a wide spread of front-drive and all-wheel-drive cars: the 2004-up Chevrolet Equinox and 2006-up Pontiac Torrent (GM codes M09 and M45), the 2003-2004 Saturn Ion and 2002-2003 Saturn Vue V6, the 2003-2007 Saab 9-3, the 2002-2008 Opel Vectra C and Signum, the 2004-2008 Nissan Maxima, Quest and Altima with the RE5F22A, the 2007-2008 Suzuki XL7, and the Volvo S60, S80 2.5T, V70, XC90 2.5T, C30, S40 and V50 T5.

The solenoids are the electrical end of the valve body, so this is the set you reach for when the gear train and clutches are still healthy but the shifting has gone bad. On this unit the classic failure is a drifting or sticking pressure control solenoid: the car bangs into gear, flares between shifts, drops into limp with a fifth-gear-only or third-gear-only feel, refuses to lock the torque converter, or shudders on light throttle at highway speed. Solenoid performance and pressure control codes usually come with it. Because all eight units age together in the same fluid, replacing the whole set at once is the only repair that sticks - swapping the one that set the code just moves the problem to the next solenoid a few months later.

Bench work is straightforward on the AW55-50SN. Drain the fluid, drop the pan and filter, unplug the internal harness at the case connector, and unbolt the valve body. Change the solenoids one bore at a time so nothing ends up in the wrong location - the shift, pressure control and TCC units look similar but are not interchangeable. Check the bore for scoring and make sure the new O-rings seat dry and unpinched before the valve body goes back up. Fill through the level plug with the correct JWS 3309 / T-IV type fluid, then reset the adaptive shift memory with a scan tool and drive it through a full relearn cycle; skipping the relearn is the usual reason a good solenoid set still shifts rough on the first drive.