Symptoms:

  • Shift quality is not load sensitive
  • Clutch pressure solenoid codes
  • Burnt clutches
  • Delayed engagement
  • Harsh shifts
  • Slide shifts
  • Slip codes
  • Slips & flares

Cause:

Wear in clutch boost valve bores causes feedback pressure instability, preventing normal shift operation.

Correction:

Recover hydraulic control and renew shift performance by reconditioning the bore and installing Sonnax oversized clutch boost valve kit.
  • 6L45, 6L50, 6L80, 6L90 Oversized Clutch Boost Valve 104740-01
  • 6L45, 6L50, 6L80, 6L90 Oversized Clutch Boost Valve 104740-01

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. Valve body casting is stamped with "lettered" locations on the far side of the core; when testing "B" or "F" location, block exhaust hole on far side of core.

6L45, 6L50, 6L80, 6L90 Oversized Clutch Boost Valve Vacuum Test Locations