Sonnax 37000-12K, Allison 1000 / 2000 / 2400 Trim Valve & Spring Kit

$ 75.00


SKU: SX 37000-12K. a20 ra b33 Categories: , Tags: ,


Allison 1000 / 2000 / 2400 Trim Valve & Spring Kit, Sonnax 37000-12K. 

Fits ’00-’09 units only. The F-trim spring is applicable to ’00-’05 valve body casting only.

The OE trim valve and spring configuration has a very conservative pressure curve, resulting in premature clutch wear in heavy-duty Allison® 1000/2000/2400 applications. Clutch damage occurs when the TCM pressure control strategy is unable to adequately raise clutch pressure and shorten shift durations. Sonnax trim valve and spring kit 37000-12K includes A-, B- and F-trim valve springs and a A- and B- trim valves with recalibrated valve ratios, which is the only way to predictably improve clutch pressures and apply rates, resulting in more responsive clutch pressure. The F-trim bore in ’00-’05 units contains an F-trim sleeve. This bore can be upgraded using the spring in this kit and Sonnax F-trim valve sleeve 37000-03.

  • 15% More clutch pressure & clamping force than OE
  • Firmer and shorter upshifts
  • Firmer TCC engagement
  • Improved engine braking on deceleration

  • A-Trim Valve & Spring
  • B-Trim Valve & Spring
  • F-Trim Spring

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Additional information

Weight 2 lbs
Dimensions 12 × 12 × 5 in