Symptoms:

  • C1 Clutch hub wear
  • Lack of C1 clutch control
  • Harsh Forward
  • Delayed bump on Forward

Cause:

The OE valve has a fixed flow rate, while C1 clutch pressure leaks to exhaust.

Correction:

Sonnax C-1 valve and seal kit includes a PTFE seal to prevent C-1 oil loss to exhaust. The new valve changes the fixed flow rate to a regulated flow rate.

1000/2000/2400

C-1 Valve & Seal Kit
Part No. 37000-05K

Fits February '04-earlier pumps. Does not fit No. 29541135 or later pump stators.

View Instructions Find a Distributor

Allison® 1000/2000/2400 OE C-1 clutch control valve has a fixed flow rate and no seal at the large spool to prevent hot fluid loss. Sonnax C-1 valve and seal kit 37000-05K controls the fill and exhaust rate of the C-1 clutch as well as reducing loss at the valve bore. The regulation contour of the Sonnax valve provides a controlled fill to reduce harsh engagements common to cold weather, long sit or Reverse to Forward abuse conditions. Controlling the flow rate reduces wear on the C-1 clutch hub. Once the valve is open, the C-1 flow is increased over OE to overcome fluid loss at the drum. The valve also has a PTFE seal to prevent incoming pressure loss to exhaust at the pump casting, which can occur under hot abuse conditions.

  • Valve changes the fixed flow rate to a regulated flow rate, reducing wear of the C-1 clutch hub
  • PTFE seal prevents C-1 oil from leaking to exhaust
  • Valve
  • Seal PTFE
  • 1000/2000/2400 C-1 Valve & Seal Kit 37000-05K
  • 1000/2000/2400 C-1 Valve & Seal Kit 37000-05K