signal accumulator piston kit sonnax 8l45 8l90Sonnax Signal Accumulator Piston Kit Fits GM 8L45 & 8L90 In GM 8L45 and 8L90 transmissions, excessive wear in the signal accumulator piston bores of the solenoid body casting can lead to shift issues, low line pressure, torque converter apply problems, and burnt clutches. These problems occur when VFS signal pressure leaks through worn bores, disrupting proper control of pressure circuits and clutch apply timing. The Sonnax signal accumulator piston