Exterior Components› Body Panels and Components
Sun Coast Converters
Suncoast Converters Boost Valve Kit - Early Style .490 Dia. O-ring Style 77898E-K
SKU: S02K 77898E-K
Moderate — 2–4 hours
Description
This kit addresses common issues in GM 4L60-E and 4L65-E transmissions such as poor line rise, leading to 3-4 clutch or 2-4 band failure, and poor shift quality. These problems often stem from a worn boost sleeve, causing oil leakage and reduced pressure rise.
The kit includes a sleeve, two O-rings, and a .490-inch diameter valve with no groove. Installing this Sonnax boost valve kit is presented as a correction to worn boost sleeves and subsequent cross-leakage or leakage to the sump.
Fitment
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Specifications
| Brand | Sun Coast Converters |
| Part Number | S02K 77898E-K |
Buy with Confidence
Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.
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