In GM 4L60-E, 4L65-E and 4L70-E units, severe wear of the TCC regulator valve bore is caused by oscillation of the OE valve allows regulated converter apply pressure to exhaust. This is a primary cause for TCC-related slip code P1870 and overheated converters. Exhausting apply pressure also diminishes line pressure, which can result in burnt clutches. Excess wear at the isolator valve bore reduces TCC apply pressure.
Reconditioning the bore and installing Sonnax TCC regulator and isolator valve kit 77754-03K restores normal TCC operation by shoring up the hydraulic integrity of this circuit.

10% Higher apply pressure
Isolator valve lengthened to operate in unworn portions of the bore
Sleeve manufactured from highly wear-resistant aluminum
Hardcoat anodized aluminum valves combat premature wear
Annular grooves help center valves in bore to reduce future side-load wear

More From This Category

MANLEY Valve, Severe Duty, Intake, 2.3 in. Head Dia, 0.311 in. Stem Dia, 5.344 in. Length, For Chevrolet BB, Set of 8

MANLEY Valve, Severe Duty, Intake, 2.3 in. Head Dia, 0.311 in. Stem Dia, 5.344 in. Length, For Chevrolet BB, Set of 8

$628.35

Sonnax Lockup Relay Control Valve Kit, Aisin Aw, Aw55-50Sn, Aw55-51Sn, Each

Sonnax Lockup Relay Control Valve Kit, Aisin Aw, Aw55-50Sn, Aw55-51Sn, Each

$99.24

Sonnax Clutch A Control Boost Valve Kit, Ford, ZF6Hp19/26/32, 6R60/75/80/100, Each

Sonnax Clutch A Control Boost Valve Kit, Ford, ZF6Hp19/26/32, 6R60/75/80/100, Each

$118.83

AFR Intake Valve, BBC 24° Stainless Steel 2.350 x 5.500 O.A.L. 11/32 Stem Race, Ea.

AFR Intake Valve, BBC 24° Stainless Steel 2.350 x 5.500 O.A.L. 11/32 Stem Race, Ea.

$55.65

COMP Cams Valve, Sportsman, Stainless Steel, Intake, For Chevrolet Small Block, 2.020 in. Head, 4.911 in. Length, Each

COMP Cams Valve, Sportsman, Stainless Steel, Intake, For Chevrolet Small Block, 2.020 in. Head, 4.911 in. Length, Each

$38.21

MANLEY Valve, Street Flo, Exhaust, 1.465 in. Head Dia, 0.3415 in. Stem Dia, 5.08 in. Length, For Ford SB, Set of 8

MANLEY Valve, Street Flo, Exhaust, 1.465 in. Head Dia, 0.3415 in. Stem Dia, 5.08 in. Length, For Ford SB, Set of 8

$280.36