August 01, 2019
Symptoms:
- Premature clutch wear
- Inability to alter clutch apply pressure curve
Cause:
OE valve and spring configuration do not allow TCM pressure control strategy to adequately raise clutch pressure and shorten shift durations.Correction:
This Sonnax kit alters the trim valves and springs, resulting in a more responsive clutch pressure.1000/2000/2400
Trim Valve & Spring Kit
Part No. 37000-12K
Fits '00-'09 units only. The F-trim spring is applicable to '00-'05 valve body casting only.
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Tooling:
- 37000-TL12
View Instructions Find a Distributor
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 ('02-'09) 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 (see Figures 2 and 3).The F-trim bore in '00-'05 units contains an F-trim sleeve (Figure 1). 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
Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.
GM Allison® 1000/2000/2400 Valve Body Layout
