Adjustments

Fig. 1: Kickdown and downshift adjustment for the R3A automatic transmission

Fig. 2: Kickdown switch check for the 3N71B automatic transmission

Fig. 3: Downshift solenoid test for the 3N71B transmission

Make sure that the accelerator pedal travels its entire stroke properly.
Turn the ignition switch to ON, but don't start the truck.
Depress the accelerator pedal as far as possible. As the throttle nears the wide open position, the contact point of the kickdown switch should close with a light click from the solenoid. The kickdown switch should begin operation at about ⁷⁄₈ of full pedal stroke.
If not, loosen the kickdown switch attaching nut and adjust the switch.
Tighten the attaching nut when adjustment is correct.
If the switch cannot be made to operate properly, replace it.