Disconnect the cable from the negative battery terminal, raise the vehicle and support it securely on jackstands, then remove the engine protection cover. Drain the engine oil, remove the oil filter adapter from the engine block, and take off the structural collar and the intake manifold support bracket. Remove the flywheel/driveplate inspection cover, then remove the mounting bolts and lower the oil pan from the vehicle, taking care to tap it gently with a soft-face hammer or a wood block if it is stuck. Exercise caution to avoid damaging the gasket surfaces. Next, remove the oil pump pickup tube and screen assembly, clean both thoroughly, and install them with a new seal. Clean the oil pan and sealing surfaces on the block and pan, ensuring all old gasket material is removed, and check for distortion. After cleaning, apply a 1/8-inch bead of ATV sealant at the cylinder block-to-oil pump assembly joint at the oil pan flange and install a new oil pan gasket. Position the oil pan and install the bolts finger tight, then tighten them to the specified torque while working side-to-side from the center out. Install the intake manifold support bracket and tighten the bolts securely. For the structural collar, place it in position between the transaxle and the oil pan, tightening the collar-to-oil pan bolts to about 30 in-lbs, then install and tighten the collar-to-transaxle bolts to 80 ft-lbs, and finally torque the structural collar-to-oil pan bolts to 40 ft-lbs.