Please provide detailed removal, and installation information.
To remove the knob, it will unscrew from the timer. For the timer to be removed, you will want to remove a screw from the endcap on the back of the unit from both sides. Once removed you will slide the bottom of the panel forward and up. Once this is done you will disconnect the wiring and connect to the new timer. Remove the screw holding the timer in place and slide the timer over and out. Install the new timer and reassemble the unit.
Whirlpool washer continually runs in every cycle without shutting off. Also water is leaking under machine during use. Could the water leak be from the washer continually running?
The unit continuously running even when it hits the off position would be a faulty timer 285938. For the leaking issue you will want to determine exactly where the leak is originating from. Check to make sure that the pressure hose has not come loose from the tub. Also check to makes sure that the leak is not around the transmission post as there could be a bad center post seal.