AW55-50SN Valve Body 2004-2009, remanufactured and ready to install. Fits the AW55-50SN. Ships fast from the USA.
Owners searching for an AW55-50SN valve body for a 2004-2009 car are usually living with one of a few complaints: a thump when Drive is selected, a 2-3 shift that flares or drops briefly into neutral, a converter that surges at light cruise, or a transmission that has gone into failsafe and now engages every gear abruptly. On the Volvo, Saab, Saturn, Opel, Nissan and Suzuki models that used this Aisin Warner five-speed, those complaints trace back to the valve body more often than to the clutches. This remanufactured unit covers the long 2004-2009 run of the transaxle and goes in as a complete hydraulic assembly.
The AW55-50SN is a five-speed front-wheel-drive electronic transaxle, and its valve body decides how hard and how fast every clutch and band applies. The transmission computer controls linear solenoids, and those solenoids are fed by a solenoid modulator valve that caps their maximum output. Downstream, the SLT solenoid raises pressure to engage the C-1 clutch through a chain of modulated valves, while separate circuits control the B-4 servo for the 2-3 shift and the multi-valve converter clutch apply. Every one of those valves rides in a machined aluminum bore. After 100,000-plus miles of fluid flow the bores open up, pressure leaks past the spools, and the computer can no longer produce the pressure it is asking for.
This transaxle rewards a pressure gauge. Transmission Digest's AW55-50SN valve body article gives the working numbers: SLT pressure should start near 5 psi in Drive and climb with throttle to about 80 psi, and C-1 pressure should step from zero in Park to 25 psi and then 50 psi within about half a second of selecting Drive. If C-1 jumps straight to around 160 psi, the computer is likely in failsafe and a code needs to be read first. For converter complaints, a cooler-flow test should show roughly 1.3 gpm with the converter released and about 0.7 gpm when it applies. Readings that stay low point at a worn regulator bore or bushings. One caution from the same source: the pressure taps use 12mm heads, and the 27mm plug is the band anchor, not a tap or fill plug. Our AW55-50SN service guide covers what happens if that anchor is disturbed and how to separate a solenoid fault from bore wear.
This valve body is listed for the AW55-50SN from 2004 through 2009. Because the same basic transaxle was calibrated differently for each automaker, and running changes happened inside that window, compare the casting numbers, solenoid layout and harness connector on your old valve body with this one before you install it, or send us your year, make, model and VIN and we will check it for you. Some Volvo applications also use a brake-signal strategy that drops C-1 to create neutral at idle, which a computer update can address, so rule that out first. If your car falls just outside these years, see the 2003-2007 AW55-50SN valve body, or browse every Aisin unit we carry on the Aisin transmission parts page.
Drain the fluid and drop the pan before unbolting the valve body, and clean the pan and magnet thoroughly; old friction debris is the fastest way to score a fresh set of bores. Refill with a JWS 3309 type fluid, not a generic multi-vehicle ATF, and check the level at the temperature the factory procedure specifies. Label every solenoid connector on the way out. If any linear solenoid tests weak, replace the set now with the AW55-50SN solenoid kit rather than moving a tired solenoid onto a new valve body. A converter that has been slipping for a while is hard on the pump, so if you hear pump whine, plan for the AW55-50SN pump at the same time. Finish with the computer's adaptive reset and several gentle drive cycles so it can relearn shift pressures on the new hardware.
| Fits | AW55-50SN 2004-2009 |
| Part type | Valve Body |
| Condition | Remanufactured |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is listed for 2004-2009 AW55-50SN applications, which covers that year. Different automakers ran their own calibrations, so match the casting numbers, solenoid layout and connector on your old valve body, or send us your VIN and we will confirm before it ships.
Use a JWS 3309 type ATF. Avoid generic multi-vehicle fluids, and set the level using the factory temperature-check procedure for your car.
This listing is the remanufactured valve body. If your solenoids test weak or you want everything new at once, we also carry an AW55-50SN valve body with solenoids and a separate solenoid kit.
Yes. Reset the transmission adaptations with a capable scan tool, then drive gently through all five gears several times so the computer relearns shift pressures. Skipping this can leave harsh shifts even with a good valve body.
Not always. If C-1 pressure jumps to around 160 psi on selection of Drive, the computer may be in failsafe from a stored code. Read and clear the code and check the wiring before you replace hardware.
