AW55-50SN Pressure Control Solenoid 2003, new and ready to install. Fits the AW55-50SN. Ships fast from the USA.
This page is for owners of a 2003-era Aisin Warner five-speed automatic, the AW55-50SN found in Volvo and Saab cars and in GM, Nissan and Suzuki applications under other names, who are dealing with a firm 1-2 shift, a bump on the 2-1 coast-down, or a converter clutch that cycles and makes the tachometer flutter at steady speed. It is a new three-piece linear solenoid set with its bracket: the SLT, SLS and SLU solenoids that control pressure in this transmission. Each solenoid is rated at 5.3 ohms, and the set is catalogued for the 2000-2014 AW55-50SN range. It ships from the USA.
Gear selection in this unit is handled by separate on/off shift solenoids. The three linear solenoids in this set control the quality of what happens: SLT shapes line pressure with throttle, SLS (normally open) controls clutch feed pressure through the shift pressure control valve, and SLU (normally closed) applies the torque converter clutch, the B-4 servo and B-2 neutral control. All three are fed by a solenoid modulator valve that caps their maximum output, and Sonnax lists the family as running at 300 Hz with a 10 to 40 percent duty cycle.
The SLU deserves special attention on this transmission. According to Sonnax it affects the 1-2 upshift, the 2-1 downshift, light-throttle converter clutch modulation, full lockup timing and lockup release on coast. It is also the one linear solenoid with a threaded adjuster: turning it in reduces SLU output for firmer shifts and later lockup, and turning it out gives softer shifts and earlier lockup. A solenoid that has drifted out of adjustment or wears internally can mimic a converter problem.
Scan the TCM for stored codes first and check fluid level by the factory method, since incorrect level alone upsets linear solenoid control. Resistance at each solenoid should be around 5.0 to 5.6 ohms. For converter clutch complaints, Sonnax recommends a cooler flow check: normal flow in Drive with the converter clutch released is about 1.3 gpm and drops to about 0.7 gpm when it applies. If you see harsh shifts but no flow change on engagement, the SLU is not reacting correctly. Also clean the input and output speed sensors and keep their wiring away from the linear solenoid wiring; Sonnax notes that signal interference can cause harsh shifts, high line pressure and phantom codes that point at good solenoids. The AW55-50SN service guide lays out these checks, and our Aisin overheating prevention guide covers the fluid damage a slipping lockup clutch leaves behind.
This listing is tagged 2003 and the set is listed for AW55-50SN applications from 2000 through 2014, so it is not limited to 2003 vehicles. What decides fit is the solenoid generation in your valve body, not the model year. Early SLT and SLS solenoids use a narrow bracket and a 1.408 inch short manifold, while late ones use a wider bracket and a 1.510 inch long manifold; the late SLT also points its connector down and needs the matching harness. The SLU is the same in both. Pull one of your old solenoids and compare it with the photos, or send us the year, model and VIN and we will check it. See everything for this family on our Aisin parts page.
A worn modulator or regulator bore calls for a replacement AW55-50SN valve body. To replace the shift solenoids at the same time, the eight-piece AW55-50SN solenoid set covers the whole valve body.
| Fits | AW55-50SN 2003 |
| Part type | Pressure Control Solenoid |
| Condition | New |
| 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.
No. The listing carries a 2003 tag, but the set is catalogued for AW55-50SN applications from 2000 to 2014. Match the bracket width and connector direction of your old SLT and SLS solenoids rather than relying on the year.
Three linear solenoids, SLT, SLS and SLU, plus the mounting bracket. The on/off shift solenoids and valve body gaskets are not included.
It often is. The SLU controls converter clutch apply and modulation, and Sonnax ties RPM fluctuation at 30 to 40 mph to SLU output. Rule out low fluid and check cooler flow before replacing the solenoids.
It is not recommended. Sonnax states the linear solenoids are calibrated to the valve body and that swapping SLT or SLS units between cores is generally not acceptable. Installing all three together gives the most consistent result.
Use the JWS 3309 type fluid your vehicle maker specifies for its Aisin five-speed, and set the level using the factory hot check procedure. Low or overfilled fluid will undo the improvement from new solenoids.
