• No ratio change
  • Ratio codes
  • Ratio errors
  • No high ratios
  • Poor fuel economy


Primary pulley boost valve/sleeve wear allows critical pressure loss, preventing precise pulley control.


Recover hydraulic control and revive proper pulley operation by installing Sonnax drop-in primary pulley boost valve kit.


Primary Pulley Boost Valve Kit
Part No. 33740-01K

You need this if... View Instructions Find a Distributor

Ford CFT30 transmissions may have difficulty properly controlling the primary pulley, resulting in ratio errors, ratio codes, and inability to access higher ratios. These troubles can often be traced to excess wear at the primary pulley boost valve/sleeve assembly. This deterioration allows critical control pressure to exhaust, preventing full control of the pulley. Installing Sonnax primary pulley boost valve kit 33740-01K returns hydraulic integrity to the circuit for renewed control under all operating conditions.

  • Annular grooves help center valve in sleeve to reduce future side-load wear
  • Lengthened critical spool for added stability and wear prevention
  • Sleeve manufactured from highly wear-resistant aluminum
  • Hardcoat anodized aluminum valve combats premature wear
  • Drop-in Zip Valve™ parts install quickly and easily
Learn More About Zip Valve™ Drop-In Repairs
  • Valve
  • 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.

Ford CFT30 Valve Body Layout

Ford CFT30 Valve Body Layout
  • CFT30 Primary Pulley Boost Valve Kit 33740-01K
  • CFT30 Primary Pulley Boost Valve Kit 33740-01K

You need this if...

Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.

CFT30 Primary Pulley Boost Valve Kit Vacuum Test Locations