Many Chrysler A904 and 42H/RE transmissions experience rear servo piston sticking/breakage, pin bore wear and reverse band slippage. The servo piston has a tendency to get cocked in the bore, inhibiting band apply. The high reverse line pressure continues to apply against a cocked piston, causing piston breakage. The bore of the piston also wears from side loading, resulting in insufficient band apply pressure. Sonnax billet aluminum rear servo piston 22912A addresses these problems.

Modified seal ridges prevent piston from sticking in case bore
Billet aluminum won’t crack like OE cast piston
2.540" O.D.

More From This Category

Sonnax Oversized Two-Spool Relay/Signal Valve Kit, Aisin Aw, 09G/K/M, Tf-80/81Sc, Tf-60Sn, Each

Sonnax Oversized Two-Spool Relay/Signal Valve Kit, Aisin Aw, 09G/K/M, Tf-80/81Sc, Tf-60Sn, Each

$67.02

Sonnax Vacuum Test Plate Kit, Allison, Allison 1000/2000/2400 '00-'15, Each

Sonnax Vacuum Test Plate Kit, Allison, Allison 1000/2000/2400 '00-'15, Each

$845.00

Sonnax Heavy Duty Output Shaft, 4L60-E, 4L65-E, 4L70-E, Each

Sonnax Heavy Duty Output Shaft, 4L60-E, 4L65-E, 4L70-E, Each

$1,125.69

TCI 4L60E .490 Boost Valve w/ O-Ring.

TCI 4L60E .490 Boost Valve w/ O-Ring.

$121.27

Sonnax Reverse Servo Spacer Kit, GM 4L80-E, 4L85-E, Each

Sonnax Reverse Servo Spacer Kit, GM 4L80-E, 4L85-E, Each

$27.08