Vacuum-operated ratio changer for a two speed axle. Sometimes removed or plugged off because the actuator diaphragm rots away and causes a vacuum leak. I repaired mine by replacing the actuator with a carbureator choke actuator from a Honda generator.

Last edited by Puffie40; 08/23/2024 5:42 PM.

1959 Canadian GMC 9600 with a dump box
Intro / Details in Big Bolts