In an Allison transmission, the ______ valve component has cams that can be adjusted to change shift points.

• A. selector
• B. shift signal
• C. shift relay
• D. governor

Answer: (B)

In an Allison automatic, how and when shifts happen is controlled by hydraulic signals that respond to vehicle speed and throttle. The shift signal valve is the component that actually sets those shift thresholds, and it does so with internal cams. These cams create specific pressure points for each gear; by adjusting the cam surfaces, a technician can change at what speeds or conditions the transmission will upshift or downshift. So, the shift signal valve is the part whose cams are adjusted to change shift points.

The other parts don’t set shift points by adjustable cams in the same way: the selector valve is for choosing drive ranges, the shift relay handles electronic/hydraulic actuation of gear changes, and the governor provides the speed-based pressure that helps determine when shifts should occur but does not carry adjustable cams that directly tune the shift points.