Symptoms:

  • Poor shift quality
  • Low line pressure
  • No converter apply
  • Hydraulic-related converter codes
  • Burnt clutches
  • Soft shifts

Cause:

Wear in the signal accumulator piston bores of the control solenoid valve body casting allows valuable VFS signal pressure loss. This pressure is used to help control shift feel, regulate line fluid pressure and control pressure of the converter clutch control valve.

Correction:

Restore hydraulic control by reconditioning the bores and installing Sonnax oversized signal accumulator piston kit.

8L45, 8L90

Oversized Signal Accumulator Piston Kit
Part No. 154740-01K


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

GM 8L45 and 8L90 units often suffer burnt clutches, shift concerns, low line pressure and/or converter apply complaints due to excess wear in the signal accumulator piston bores in the control solenoid valve body casting. This wear allows valuable VFS signal pressure to exhaust, preventing proper shift control, line pressure regulation and/or converter clutch apply.

Reconditioning these bores and installing Sonnax oversized signal accumulator piston kit 154740-01K re-establishes correct clearance for proper VFS signal pressure.

  • Hardcoat anodized aluminum pistons combat premature wear
  • Annular grooves reduce wear rate
  • Accumulator Pistons (7)
  • 8L45, 8L90 Oversized Signal Accumulator Piston Kit 154740-01K
  • 8L45, 8L90 Oversized Signal Accumulator Piston Kit 154740-01K

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 Oversized Signal Accumulator Piston Kit Vacuum Test Locations