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Kit, Sleeve, Boost, Valve, .490" Diameter, Early Pump, 4L60E, 4L65E, 4L70E, GM (93-05)

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77898E-3K
77898E-3K Kit, Sleeve, Boost, Valve, .490" Diameter, Early Pump, 4L60E, 4L65E, 4L70E, GM (93-05Boost Valve Kit, 4L60-65E, 4L70E, GM, "Factory" Style 4L60E,4L65E Early pump design, .490" Dia., Factory style sleeve, no o-ringsGM Factory Style Boost Valve Kit, 4L60E, 4L65E, 4L70E
Price: $27.18
Part Number: TAT-77898E-3K-SX

Boost Valve Kit, 4L60E,4L65E, 4L70E, GM, "Factory" Style,.490" diameter  

Vehicles with a 4L60-E, 4L65-E or 4L70-E transmission frequently have poor line rise, which can result in 3-4 clutch, 2-4 band failure or poor shift quality. The duty cycle of the EPC solenoid causes the boost sleeve to wear quickly. Oil entering the torque signal orifice leaks past the boost valve and exhausts at the reverse orifice, resulting in poor line rise. Reverse oil can exhaust both to the sump and back through the torque signal orifice. The outside diameter of the boost sleeve also allows some leakage through the pump body, which decreases pressure rise.

Sonnax offers four versions of reverse boost valve and sleeve kits for early pumps. There are two O-ringed versions, 77898E-K for oversized ratio and 77898E-4K for OE ratio, and two factorystyle versions, 77898E-3K for oversized ratio early pumps and 77898E-6K for OE ratio.

*NOTE: The 4L60-E, 4L65-E and 4L70-E transmissions will not function properly if the wrong early vs. late design assembly is installed.

Sonnax boost valve kit 77898E-3K is an increased ratio assembly that will restore hydraulic integrity and prevent leakage in units with early-design pumps. See chart for usage details and other boost valve options.


Contents

Sleeve

Valve .490", No Groove

Warning:

OE has made multiple pump design changes. Transmission will not function properly if the wrong length sleeve is installed. Verify length of OE sleeve and select Sonnax kit with equivalent sleeve length.

EPC Spool OE Valve/Sleeve Design Sonnax with O-Rings Sonnax “Factory Style”
Early Pump Design, 1.907" Long Sleeve
.421" Valve: 1 Band

No Sonnax ratio available.

Sonnax 77898E-4K may be used, but noticeably firmer shifts will occur.

No Sonnax ratio available.

Sonnax 77898E-6K may be used, but noticeably firmer shifts will occur.

Sleeve: No Groove
.470" Valve: 2 Bands 77898E-4K Valve: 1 Groove 77898E-6K Valve: 1 Groove
Sleeve: 1 Groove Sleeve: No Groove Sleeve: No Groove
.490"
Upgrade for OE .470"
Valve: N/A 77898E-K Valve: No Groove 77898E-3K Valve: No Groove
Sleeve: N/A Sleeve: No Groove Sleeve: No Groove
Late Pump Design, 1.809" Length (Short) Sleeve
.421" Valve: 3 Bands 77898E-14K Valve: 3 Grooves

No Sonnax ratio available.

Sleeve: No Groove Sleeve: No Groove
.472" Valve: 4 Bands 77898E-16K Valve: 4 Grooves

No Sonnax ratio available.


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