Transmission Parts Aisin AW 55-51SN 55-50SN Valve Body Valve Body
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Warning:

Units are very similar in appearance, but vary by early and late, and manufacturer application – and cannot be interchanged. Reference the Sonnax identification guide to verify the correct valve body is installed.

55-50SN, 55-51SN

Remanufactured Valve Body
Part No. AW55GE

GM, Early, “A” or No Letter Casting. Also fits AF23/33 units.

Tech & Install Tips Find a Distributor

Sonnax remanufactured valve body AW55GE has been designed to address a host of common issues, such as: 2-3 shift concerns; delayed engagements; no lockup; burned clutches; inadequate lubrication failures; loss of gears; and various harsh upshift and downshift complaints.

To guarantee the highest level of operational performance, this remanufactured valve boy is tested on state-of-the art equipment to verify that line pressure, solenoid modulator pressure, clutch pressures, and converter pressures match OE standards.

Remanufactured solenoids are included, and are independently tested for performance, then tested and tuned on the remanufactured valve body to ensure the unit functions correctly and is ready for bolt-in and the required re-adapt process in vehicle.

  • 55-50SN, 55-51SN Remanufactured Valve Body AW55GE

55-50/51SN Valve Body Identification

The transaxle is manufactured by Aisin Warner, but is used by many car makers. Volvo calls it an AW55-50, Nissan and Infiniti call it an RE5F22A, GM (Chevy, Saab, Saturn and Pontiac) calls it an AF33-5.

Part Number Chart

Vehicle TypeEarly/LateHas B5 SpringPart Number
GM/Saab/Saturn/SuzukiEarlyNo AW55GE
GM/Saab/Saturn/SuzukiLateNo AW55GL (Warranty Only)
GM/Saab/Saturn/SuzukiLateYes AW55GMLSP (Warranty Only)
VolvoEarlyNo AW55VE (Warranty Only)
Volvo/NissanLateNo AW55VL (Warranty Only)
Volvo/NissanLateYes AW55NL


Identify Vehicle Type

If vehicle type is not known check the S2 solenoid. A domed top on the S2 is a GM/Saab/Saturn/Suzuki. A flat top with four ribs radiating from the hole in the center of the S2 is a Nissan/Volvo.

GM/Saab/Saturn/SuzukiVolvo/Nissan


Identify Early/Late

Look for a letter cast into the valve body to the right of the S4 solenoid hold-down bolt.
  • "No Letter/Blank Space" and valve bodies cast with a letter "A" are considered early.
  • Valve bodies cast with a letter "B" or "C" are considered late.


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Check for B5 Spring

In model years '05-later, all Nissan and most GM/Volvo valve bodies may have a spring under the B5 control valve. It is very important to check the 10th digit of the VIN to verify production year. If the 10th digit of the VIN is 5 or higher, check your original valve body for a B5 control valve spring as shown. CAUTION: The wrong valve body will cause shift quality concerns.

Remove the two-bolt end plate as shown here and check under the B5 control valve to see if there is a spring.

SpringNo Spring
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55-50/51SN Solenoid & Bracket Identification

To avoid solenoid damage, please return the core in the Sonnax box with formed foam packaging that contained the purchased remanufactured valve body.

Bracket Identification

Brackets are specific to code of valve body. The "No Code" valve bodies use the narrow bracket with small notch above SLS solenoid. The "A", "B", and "C" coded valve bodies use the wide bracket with a large notch above the SLS solenoid.

Solenoid Identification

No code or code A valve bodies have the SLT and SLS electrical connector facing up. Code B or C valve bodies have the SLT and SLS electrical connectors facing down.

Narrow Bracket and Upward-Facing ConnectorsWide Bracket and Downward-Facing Connectors

Solenoid Wire Color Chart

SolenoidConnector ColorWire Color
SLUBlack1 Green, 1 Brown
SLTBlue1 Green, 1 Gray
SLSGreen1 Blue, 1 Red
S1BlackWhite
S2Black or GrayBlack
S3GrayYellow
S4Blue or GreenPurple or Red
S5Green, Red or GrayBlue or Black
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