Howdy, neighbor. Here's the process from the shop manual:
SECTION 501-16: Wipers and Washers 2002 Explorer Sport/Sport Trac Workshop Manual
REMOVAL AND INSTALLATION Procedure revision date: 01/17/2002
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Windshield Wiper Motor
Removal
Disconnect the washer hose from the LH washer jet nozzle.
Remove the cowl grilles; for additional information, refer to Section 501-02.
Unsnap the wiper motor clip from the RH wiper mounting arm and pivot shaft.
Disconnect the RH wiper mounting arm and pivot shaft from the LH wiper mounting arm and pivot shaft and move both away from the windshield wiper motor.
Disconnect the electrical connector.
Remove the ground strap nut and position the strap aside.
CAUTION: The internal permanent magnets used in the windshield wiper motor are made of a glass-like material. To avoid damaging the magnets, do not strike the motor with a hammer or any other object.
Remove the windshield wiper motor.
Remove the stud bolts.
Remove the bolts.
Installation
CAUTION: The internal permanent magnets used in the windshield wiper motor are made of a glass-like material. To avoid damaging the magnets, do not strike the motor with a hammer or any other object.
Install the windshield wiper motor.
Install the windshield wiper motor.
Install the stud bolts.
Install the bolts.
Install the ground strap and nut.
Connect the electrical connector.
Install the wiper mounting arm and pivot shaft arms to the windshield wiper motor.
Install the LH wiper mounting arm and pivot shaft onto the windshield wiper motor crank pin.
Install the RH wiper mounting arm and pivot shaft onto the wiper motor crank pin.
Push the retaining clip until it snaps into place.
Install the cowl grilles. For additional information, refer to Section 501-02.
Connect the washer hose to the LH washer jet nozzle.
Install the LH wiper pivot arm. Refer to Wiper Pivot Arm—Front in this section.
Adjust the LH wiper pivot arm. Refer to Windshield Wiper Blade and Pivot Arm Adjustment in this section.
Now, with all that in mind, are you sure it's not the wiper blades? Maybe one of the pivot points on the linkage?
Oh, and removing the cowl is simple: Remove the wiper arms, then remove the single screw in the center (the right edge of the driver's side cowl piece). Then, pull up on the pieces to release the slips, driver's side first.
Good luck!
-Joe