55-50SN, 55-51SN

Remanufactured Valve Body
Part No. AW55GMLSP

GM, ’05-Later, with B5 Spring. Also fits AF23/33 units.

Tech & Install Tips Find a Distributor

Sonnax remanufactured valve body AW55GMLSP 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 AW55GMLSP

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
VolvoEarlyNo AW55VE
Volvo/NissanLateNo AW55VL
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.


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.


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

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
S2Black or GrayBlack
S4Blue or GreenPurple or Red
S5Green, Red or GrayBlue or Black