To start with the 722.3 trans DOESN'T have plastic governor gears!! ONLY the 722.4(small trans) has plastic gears!
With the cable disconnected the trans should shift into 4th by 25MPH under light throttle.
YES springs in the
VB can break & pistons will seize as well for NO apparent reason.
You can check governor operation if you want (send private message to me if you wany more info about that test!).