• Overheating
  • Code P0741
  • TCC surge


Wear of the F-trim valve end sleeve allows TCC PWM control oil to leak to exhaust and can also cause the valve to stick.


Overcome OE design flaws and avoid oil cut-off by installing the improved Sonnax drop-in accumulator control valve kit.


F-Trim Valve End Sleeve
Part No. 37000-03

Fits '00-'05 units only.

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The F-trim valve in Allison® 1000/2000/24000 units is controlled by a PWM solenoid that continuously strokes the valve. When the valve end sleeve becomes worn from constant oscillation, it allows TCC PWM pressure to leak to exhaust, inhibiting the valve from stroking against the spring and causing converter apply concerns, TCC surge, TCC slippage, code P0741 and overheating. The valve end sleeve also can become worn enough to cause the valve to stick, causing converter release problems as well as apply problems, depending on which direction the valve gets stuck. Sonnax F-trim valve end sleeve 37000-03 is wear-resistant and has high lubricity characteristics to restore the F-trim valve to normal operation.

  • Sleeve is made from high-quality aluminum for increased wear resistance
  • High lubricity ensures proper valve operation
  • Drop-in Zip Valve parts install quickly and easily
Learn More About Zip Valve™ Drop-In Repairs

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

GM Allison® 1000/2000/2400 Valve Body Layout
  • 1000/2000/2400 F-Trim Valve End Sleeve 37000-03
  • 1000/2000/2400 F-Trim Valve End Sleeve 37000-03