The solenoid regulator valve ensures that the solenoids are not flooded with more pressure than they can exhaust. When the regulator valve sticks, the pressure becomes too high and the unit may exhibit wrong gear starts. A more common problem is wear in the solenoid regulator bore, causing working pressure to be too low. Low solenoid pressure results in no 2nd, no 3rd or a shift to neutral on a 3-4, 4-3 shift. Sonnax solenoid regulator valve kit 76948-14K prevents both sticking and leaking. Sonnax bore sizing tool 76948-BST2 is required to fit this valve to a closer tolerance.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg., or if wear is visually detected.