[. . . ] WALK BEHIND POWER MOWER DRIVE SYSTEMS SERVICE MANUAL ABOUT THIS MANUAL This service manual was written expressly for Toro servicing dealers. The Toro Company has made every effort to make the information in this manual complete and correct. This manual was written with the assumption that the reader has basic mechanical knowledge and skills. This book contains material covering the Toro and Lawn-Boy Walk Behind Mower Drive Systems models from 1990 through 2006, and may be specified for use on products built after 2006 that are similar in design. [. . . ] Check the innermost groove on the output shaft which is located 2-1/4" (5. 7cm) in from the end of the shaft; make sure that the O-ring seal is present and intact. Press the needle bearing and the oil impregnated bushing from the pivot arm using an arbor press. Removal of the grease fitting is not recommended because it is pressed in. However, if damaged or lost, we suggest tapping and installing a threaded grease fitting. If the spring arm knob requires replacement, push in on the detent tab, then pull the knob straight off. Note: The detent rivet is not replaceable. Rear Height-of-Cut and Wheel Pinion Clutch - Assembly 1. Pack the caged needle bearing with grease, then press into the outside of the pivot arm until it is flush with the groove that houses the externally tabbed thrust washer. Press the oil impregnated bushing into the boss on the pivot arm until it is flush with the face of the boss. If spring arm disassembly was required, install the knob making sure that the detent is pressed out about . 060" (1. 5mm). Install the spring arm knob so that the concave side of the knob and the convex side of the rivet align. Fig 137 gearcase wheel assy 2 WPM Drive Systems Manual 5-5 WHEEL PINION CLUTCH 4. Slide the externally tabbed thrust washer and the internally tabbed thrust washer onto the output shaft. Make sure that the tab on the internally tabbed thrust washer enters the keyway. Place the friction ring into the groove on the pivot arm, flat side out. Slide the clutch washer onto the shaft so that the recesses for the key are facing out. Place the wheel pinion key in the groove on the output shaft with the leg toward the clutch washer. You are using the correct key if, when placed in the groove, the top of the key is flat and the straight portion of the leg is perpendicular to the shaft. Before assembling further, rotate the clutch washer back and forth slightly, making sure that the key actuates properly (Fig. To increase service life, make sure all parts are clean prior to assembly and coated with new grease. If removed, install a new O-ring in the innermost groove 2-1/4" (5. 7cm) in from the end on each output shaft, making sure that it is fully seated in the groove. Slip the end cap onto the output shaft, but do not fasten at this time. Slide the pivot arm and spring arm assembly onto the output shaft, boss first. Note: The convex side of the spring arm rivet and the concave side of the knob on the spring arm should both be facing the housing. A B Fig 138 3428-0028 C D A. [. . . ] This is necessary to access the pulley and belt guide on top of the transmission. See Single Speed Bevel Gear Transmission, Rear Wheel Drive Models, Transmission Removal and Belt Replacement, see page 3-10. Do not bend the belt guides or force the belt between the pulley and belt guide. Drain the gas and oil before tipping the mower to avoid fuel spillage. [. . . ]