Cost $155 for the part (reman) for a 2000 F150 4.6 liter. Very easy to replace. Remove, test(at Autozone) and replace took about 1.25 hours. Remove negative battery cable. Take off plastic intake parts going to the throttle body, remove belt from alternator, 3 bolts hold on the alternator. Remove the electrical connectors. Reverse process for installation. Hint: For leverage on the 1/2 inch ratchet you use to move the belt tensioner, a 2 foot piece of pvc or other pipe will make getting the belt back on easier.