• High line pressure
  • Harsh shifts
  • Low cooler flow
  • Loss of lube oil
  • Overheated transmission & converter


Wear of the OE pressure regulator shuttle valve sleeve due to continuous movement of the shuttle valve prevents proper line pressure control.


Install the drop-in Sonnax O-ringed shuttle valve kit with upgraded materials and increased critical valve-to-sleeve sealing engagement to restore hydraulic integrity and prevent future wear.

8L45, 8L90

O-Ringed Shuttle Valve Kit
Part No. 154740-30K

You need this if... View Instructions Find a Distributor

Vehicles with a GM 8L45 or 8L90 transmission may exhibit high line pressure that results in harsh shifts, loss of cooler and lube flow and overheating of the transmission and converter. These problems may be caused by continuous oscillation of the shuttle valve within the shuttle sleeve, creating excessive wear and a path for balance line pressure at the pressure regulator valve to exhaust. This prevents proper positioning of the pressure regulator valve and can keep it in the higher pressure position. When in this position, bypass of excess pressure is not allowed and converter/lube/cooler feed pressure is greatly reduced.

Sonnax O-ringed shuttle valve kit 154740-30K has upgraded materials, O-rings on sleeve to provide positive sealing, minimal clearances to prevent wear and restore proper hydraulic control. The length of the critical shuttle valve diameter has also been lengthened to provide better sealing and durability.

  • Shuttle sleeve is manufactured from highly wear-resistant billet aluminum to prevent wear
  • O-Rings added for positive sealing to prevent critical fluid from cross-leaking
  • Hardcoat anodized aluminum valve combats premature wear
  • Critical valve spool made 30% longer than OE for added sealing and durability
  • Drop-in Zip Valve™ parts install quickly and easily
Learn More About Zip Valve™ Drop-In Repairs
  • Valve
  • Sleeve
  • O-Rings (3) (1) Extra
  • 8L45, 8L90 O-Ringed Shuttle Valve Kit 154740-30K
  • 8L45, 8L90 O-Ringed Shuttle Valve Kit 154740-30K

You need this if...

Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.

8L45, 8L90 O-Ringed Shuttle Valve Kit Vacuum Test Locations