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Symptoms:

  • 2-3 Harsh
  • 3-4 Harsh
  • 4-5 Harsh
  • B1 Clutch burned
  • B2 Clutch burned
  • C2 Clutch burned
  • High line pressure
  • Low Reverse pressure

Cause:

Excess wear of OE shift pressure control sleeve allows critical SLS pressure to exhaust, resulting in driveability concerns.

Correction:

Recover hydraulic control and renew shift performance by installing Sonnax shift pressure control plunger valve kit.

55-50SN, 55-51SN

Shift Pressure Control Plunger Valve Kit
Part No. 59947-75K

Also fits AF 23/33 and RE5F22A units.

You need this if... View Instructions

The shift pressure control plunger valve in Aisin AW 55-50SN and 55-51SN units utilizes shift control solenoid fluid pressure (SLS) to regulate the inboard shift pressure control valve. This controls Drive and Reverse fluid pressure to manage second clutch (B2), second coast clutch (B1) or direct clutch (C2) application.

The constant oscillation of the valve within the sleeve creates wear, allowing crucial SLS pressure to exhaust. This can result in shift concerns, high line pressure, and burnt clutches. Installing Sonnax shift pressure control plunger valve kit 59947-75K restores hydraulic integrity to this circuit with upgraded materials to prevent future deterioration.

  • Hardcoat anodized aluminum valve combats premature wear
  • Sleeve manufactured from highly wear-resistant aluminum for added durability
  • Valve
  • Sleeve

September 30, 2005

Anatomy of a Transmission: Oil Flow in the Pump-PR-Converter-Cooler Lube Circuits

Gregg Nader

Topics: Diagnostics And Theory Transmission

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  • 59947 75k combo
  • 59947 75k

You need this if...

Prior to removal, the inboard shift pressure control valve should be checked for excess wear by vacuum testing (Figure 1). If testing at the port indicated fails to hold the recommended minimum in-Hg, replace with Sonnax shift pressure control valve kit [59947-38K].

If shift pressure control valve passes testing, proceed to test shift pressure control plunger valve and sleeve (Figure 2). If testing at the port indicated fails to hold the recommended minimum in-Hg, install Sonnax shift pressure control plunger valve kit 59947-75K.

  • 59947 75k test1
  • 59947 75k test2