Vehicles with listed Ford and GM transmissions may exhibit no line rise or low line pressure due to excess wear in the isolator valve bore. The isolator valve is in the main line pressure circuit and acts as a damper to smooth pulses from the pressure control solenoid. In addition to this wear, the OE isolator spring is under high stress and commonly breaks. Spring failure allows the end plug to shift toward the middle of valve body, allowing unrestricted exhaust for main line pressure. Spring breakage can also cause isolator valve to jam in the bore, preventing the dampening effect that protects against line pressure instability. Either of these concerns can lead to undesirable shift operation and burned clutches. Installing Sonnax isolator valve kit 124740-03K restores proper line pressure control for renewed shift feel and performance.

• O-Rings added to valve and end plug to ensure positive seal
• Annular grooves help center valve in bore to reduce future side-load wear
• Spring shot-peened to reduce fatigue and eliminate premature failure
• Drop-in Zip Valve™ parts install quickly and easily