Hyundai/Kia vehicles with A4CF1, A4CF2 transmissions may exhibit insufficient line rise in the drive ranges and excessively high pressures in reverse. This may be caused by continuous oscillation of the boost valve within the sleeve, creating excessive wear and a path for EPC and reverse pressures to leak. The Sonnax boost valve kit 84741-01K has upgraded wear-resistant materials and minimal clearance to prevent wear and restore proper hydraulic control. The two-spool lands have also been designed to provide more sealing engagement with the sleeve and annular grooves are added to hydraulically center the valve within the sleeve.
Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.
A vacuum test at the ports indicated holds 18 in-Hg or more. If poor vacuum results are discovered at the OE pressure regulator valve, Sonnax PR valve kit [84741-03K] should be installed.