With the key on get someone to go in the car and press the accelerator to kick down while you go underneath the passengers side on the transmission and listen for the sylenoid to activate. The control cable also on the car could be out of adjustment but usually you will get a quick or long shifts when this is the case. If the sylenoid does not activate it most probably is the sylenoid ( switches go bad they usually stick in kickdown , transmission wont shift into higher gears) but dont rule out the switch. Good luck.
