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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

Shift Pressure Control Plunger Valve Kit
  • 59947-75k_combo

  • Shift Pressure Control Plunger Valve Kit

Small_59947-75k_combo Small_59947-75k

55-50SN, 55-51SN

Shift Pressure Control Plunger Valve Kit

Part No. 59947-75K

  • Valve
  • Sleeve

Also fits AF 23/33 and RE5F22A units.

Complaint:

  • 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.

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

Related Parts

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.

  • Test Locations
  • Test Locations

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