Boost Valve Kit - Early Style, .490" Dia., Factory Style
Description
Early style, .490" dia., increased ratio, factory style
GM 4L60-E and 4L65-E transmissions 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 boost valve kit 77898E-3K is an increased ratio assembly that will restore hydraulic integrity and prevent leakage in units with early-style pumps. Drop-in Zip Valve™ parts install quickly and easily. See chart for usage details and other boost valve options.
- Sleeve
- Valve .490", No Groove
Symptoms:
- 3-4 Clutch failure
- 2-4 Band failure
- Low line rise
- Poor shift quality
Cause:
A worn boost sleeve can allow torque signal and Reverse oil cross-leakage or leakage to sump.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 Style, 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 Style, 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. |
|
Details
- SC-77898E-3K
- SC-77898E-3K
- Sonnax
- New
Categories
Shipping Information
- Item Requires Shipping
- 1.0 lbs.
- W8.5000” x H3.5000” x L3.5000”
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