MAIN BOOST VALVE & SLEEVE KIT 55-50SN
# 74791K

Main Boost Valve & Sleeve

MAIN BOOST VALVE & SLEEVE KIT 55-50SN

Symptoms:

  • Delayed Reverse
  • Erratic Reverse pressure
  • Delayed Drive
  • Soft upshifts
  • Harsh upshifts

Cause:
The valve within the sleeve separates reverse boost oil from throttle signal (SLT) oil. Pressure in reverse can either be delayed or added to SLT, which results in very high reverse pressure. If the sleeve is worn and selector is not in Reverse, SLT is allowed to vent at the manual valve, reducing line rise, which affects engagements and shift quality.

Correction:
The tightly toleranced, drop-in replacement Sonnax valve and sleeve assembly restores proper hydraulic clearances and uses upgraded materials to prevent wear.


  • Sleeve is manufactured from highly wear-resistant billet aluminum.
  • Valve is made of hard-coat anodized aluminum to prevent wear.

Note:
Also fits AW55-51SN, AF 23/33 and RE5F22A units. 


Content:

  • Valve
  • Sleeve

SONNAX Installation Instructions

Type of Product: Sundry Parts
Qty Needed:
Years:
Alternative #:
Availability: 3, 3, 3