The throttle valve plug wears the sleeve, allowing throttle valve feed oil to leak past the plug and exhaust.
The replacement kit has been designed to eliminate excessive leakage and includes a tightly toleranced, wear resistant sleeve.
Uncontrollable throttle pressure due to oil loss is a common complaint in vehicles with an AOD transmission. This results in low line pressure and poor throttle and shift timing adjustments. The hardened steel throttle valve plug continuously reciprocates within the aluminum throttle valve sleeve, wearing the inside diameter of the sleeve. This wear allows throttle valve feed oil to leak past the plug and exhaust, resulting in poor line rise.