In GM 4L60-E, 4L65-E and 4L70-E units it is common for the plastic Forward accumulator piston to wear or crack. This causes a loss of fluid, resulting in delayed engagement, slips, burnt clutches and/or bands. Repeated reciprocation of the accumulator piston causes the piston pin bore to wear, while fluid loss through the piston pin bore or cracks causes Forward clutch to slip. Sonnax pinless Forward accumulator piston kit 77987-01K eliminates these problems.

Dual seals stabilize and completely seal the bore, providing a tight seal even after thousands of cycles
Pinless design eliminates the possibility of pin leakage, and the additional length stabilizes the piston to prevent piston cocking
Includes steel balls for plugging existing pin bore in valve body
Drop-in Zip Valve™ parts install quickly and easily

Learn More About Zip Valve™ Drop-In Repairs

More From This Category

Wilwood Bracket, Front, Radial Mount, Aluminum, 5.98 Mount Center, 3/8-24 Thread, 12.19 in. Rotor, LH or RH, Each

Wilwood Bracket, Front, Radial Mount, Aluminum, 5.98 Mount Center, 3/8-24 Thread, 12.19 in. Rotor, LH or RH, Each

$347.12

Wilwood Brake Kit, Rear, FDLI, Disc/Drum, Integral, Plain Face, Type III Ano, Kit

Wilwood Brake Kit, Rear, FDLI, Disc/Drum, Integral, Plain Face, Type III Ano, Kit

$1,912.31

Wilwood Spacer, Bracket, Gp300C, .820 Length, Rear 2000, Chrome

Wilwood Spacer, Bracket, Gp300C, .820 Length, Rear 2000, Chrome

$36.02

Wilwood Bolt, Hex Head, Alloy Steel, Grade 8, Hex, 3.000 in. Length, 5/8-18 Thread, Kit

Wilwood Bolt, Hex Head, Alloy Steel, Grade 8, Hex, 3.000 in. Length, 5/8-18 Thread, Kit

$12.10

Wilwood Brake Kit, Front, Sx6R Big Brake Dynamic, Radial, 14.00 Rotor, Plain Face, Black, Art Morrison, For Cadillac, For Chevrolet, Kit

Wilwood Brake Kit, Front, Sx6R Big Brake Dynamic, Radial, 14.00 Rotor, Plain Face, Black, Art Morrison, For Cadillac, For Chevrolet, Kit

$5,943.97

Wilwood Brake Kit, Front, FNSL6R Big Brake (Hub), Radial, 14.00 Rotor, Plain Face, Black, Art Morrison, Roadster, Kit

Wilwood Brake Kit, Front, FNSL6R Big Brake (Hub), Radial, 14.00 Rotor, Plain Face, Black, Art Morrison, Roadster, Kit

$4,200.21