Symptoms:

  • No 4th
  • No 5th
  • No 6th
  • Low clutch oil pressure
  • Harsh shifts
  • Flare shifts

Cause:

Excess actuator feed limit (AFL) bore wear allows pressure loss that leads to driveability concerns.

Correction:

Recover hydraulic control and renew shift performance by installing drop-in Sonnax sleeved actuator feed limit valve kit.

6T30 (Gen. 1), 6T30 (Gen. 2), 6T31 (Gen. 3 6T40), 6T35 (Gen. 3 6T40), 6T40 (Gen. 1), 6T40 (Gen. 2), 6T41 (Gen. 3 6T40), 6T45 (Gen. 1), 6T45 (Gen. 2), 6T46 (Gen. 3 6T40), 6T50 (Gen. 1), 6T50 (Gen. 2), 6T51 (Gen. 3 6T40)

Actuator Feed Limit Valve Kit
Part No. 144740-39K

You need this if... View Instructions Find a Distributor

The function of the actuator feed limit (AFL) valve is to provide regulated pressure to shift solenoids. Wear in the AFL bore causes low clutch pressure and results in transmission slips/harsh shifts. This eventually leads to a loss of 4th through 6th Gears, and finally the loss of transmission function.

Installing Sonnax actuator feed limit valve kit 144740-39K renews the hydraulic integrity of this circuit, restoring normal shift operation and feel in all ranges for GM Gen. 1 and Gen. 2 6T30/40/45/50 and 6T35/31/41/46/51 (Gen. 3 6T40) units. This drop-in sleeve/valve assembly provides a new and unworn bore for hydraulic sealing of the valve while the sleeve seals off existing moderate bore wear to prevent fluid loss. A new spring to provide correct limit pressure with the sleeve/valve assembly is also provided.

  • Hardcoat anodized aluminum valve combats premature bore wear
  • Highly wear-resistant, billet sleeve seals bore from wear-related fluid loss and provides a new, unworn bore for the valve to operate within
  • New spring provided for correct limit pressure
  • Drill and plug included to allow for quick rerouting of balance oil at the separator plate
  • Drop-in Zip Valve™ parts install quickly and easily
Learn More About Zip Valve™ Drop-In Repairs
  • Sleeve
  • Valve
  • Spring
  • Clip
  • Drill Bit Not Shown
  • Plugs (2) 1 Extra, For Separator Plate, Not Shown
  • 6T30 (Gen. 1), 6T30 (Gen. 2), 6T31 (Gen. 3 6T40), 6T35 (Gen. 3 6T40), 6T40 (Gen. 1), 6T40 (Gen. 2), 6T41 (Gen. 3 6T40), 6T45 (Gen. 1), 6T45 (Gen. 2), 6T46 (Gen. 3 6T40), 6T50 (Gen. 1), 6T50 (Gen. 2), 6T51 (Gen. 3 6T40) Actuator Feed Limit Valve Kit 144740-39K
  • 6T30 (Gen. 1), 6T30 (Gen. 2), 6T31 (Gen. 3 6T40), 6T35 (Gen. 3 6T40), 6T40 (Gen. 1), 6T40 (Gen. 2), 6T41 (Gen. 3 6T40), 6T45 (Gen. 1), 6T45 (Gen. 2), 6T46 (Gen. 3 6T40), 6T50 (Gen. 1), 6T50 (Gen. 2), 6T51 (Gen. 3 6T40) Actuator Feed Limit Valve Kit 144740-39K

You need this if...

Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.

Note: Due to the design changes on the Sonnax sleeve and valve, post-install vacuum testing at the inboard port is not a valid sealing test.

6T30 (Gen. 1), 6T30 (Gen. 2), 6T31 (Gen. 3 6T40), 6T35 (Gen. 3 6T40), 6T40 (Gen. 1), 6T40 (Gen. 2), 6T41 (Gen. 3 6T40), 6T45 (Gen. 1), 6T45 (Gen. 2), 6T46 (Gen. 3 6T40), 6T50 (Gen. 1), 6T50 (Gen. 2), 6T51 (Gen. 3 6T40) Actuator Feed Limit Valve Kit Vacuum Test Locations
6T30 (Gen. 1), 6T30 (Gen. 2), 6T31 (Gen. 3 6T40), 6T35 (Gen. 3 6T40), 6T40 (Gen. 1), 6T40 (Gen. 2), 6T41 (Gen. 3 6T40), 6T45 (Gen. 1), 6T45 (Gen. 2), 6T46 (Gen. 3 6T40), 6T50 (Gen. 1), 6T50 (Gen. 2), 6T51 (Gen. 3 6T40) Actuator Feed Limit Valve Kit Vacuum Test Locations