1/2" Drive Diesel Fan Clutch Wrench 48mm. Use in Conjunction With the Universal Pulley Holder (3900) to Remove and Replace the Thermostatic Fan Assembly on Ford 6.9-L, 7.3-L, and 7.3-L Diesel Engines. Use With 1/2" Drive Tools and a Torque Wrench. Refer to Factory Service Manual for Torque Specifications and Thread Direction. Wrench Opening is 48mm (1.889"). .