Symptoms:

  • Low line rise in Drive
  • Soft shifts
  • Burnt clutches

Cause:

Wear of the boost valve sleeve allows EPC fluid pressure escape to exhaust.

Correction:

This Sonnax boost valve kit has upgraded materials and minimal clearances to prevent wear and restore proper hydraulic control.

6L45, 6L50, 6L80, 6L90

Boost Valve Kit
Part No. 104520-01K

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

Vehicles with listed GM transmissions may exhibit insufficient line rise in drive ranges, soft shifts and/or burnt clutches. These problems may be caused by continuous oscillation of the boost valve within the boost sleeve, creating excessive wear and a path for EPC fluid pressure to leak to exhaust. Sonnax boost valve kit 104520-01K has upgraded materials and minimal clearances to prevent wear and restore proper hydraulic control. The sleeve also has a slightly larger EPC feed orifice to provide quicker throttle response.

  • Boost sleeve is manufactured from highly wear-resistant billet aluminum to prevent wear
  • Larger feed orifice provides quicker throttle response
  • Restores proper line rise
  • Valve
  • Sleeve

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 6L45, 6L50, 6L80, 6L90 Valve Body Layout

GM 6L45, 6L50, 6L80, 6L90 Valve Body Layout
  • 6L45, 6L50, 6L80, 6L90 Boost Valve Kit 104520-01K
  • 6L45, 6L50, 6L80, 6L90 Boost Valve Kit 104520-01K

You need this if...

A vacuum test at the port indicated fails to hold at least 18 in-Hg.

6L45, 6L50, 6L80, 6L90 Boost Valve Kit Vacuum Test Locations