• Low line rise in Reverse
  • Low line rise
  • No line rise
  • 1-2 Flare
  • 2-3 Flare
  • Delayed Reverse


A worn boost valve sleeve allows TV boost and Reverse pressures to cross-leak or leak to exhaust.


Sonnax drop-in boost valve kit restores the hydraulic integrity of the circuits with tight tolerances.


Boost Valve Kit
Part No. 86940-05K

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In vehicles with Ford ATX transmissions, reduced/no line rise, delayed Reverse and flare 1-2, 2-3 upshift complaints can be caused by a worn boost sleeve. Wear at this sleeve allows leakage between the TV boost and reverse circuits. Sonnax boost valve kit 86940-05K eliminates this cross-leakage and restores the hydraulic integrity of the circuit.

  • Sleeve is manufactured from highly wear-resistant aluminum to prevent wear
  • Kit can be used to replace any of the OE boost ratio size variations
  • Drop-in Zip Valve™ parts install quickly and easily
Learn More About Zip Valve™ Drop-In Repairs
  • Valve
  • Sleeve
  • ATX Boost Valve Kit 86940-05K
  • ATX Boost Valve Kit 86940-05K