Remove the oil pan and unbolt the oil pump, lowering it from the engine. The oil pump driveshaft will come out with the pump as it is lowered, characterized by a rod with flat-sided portions at each end. If the pump is defective, replace it with a new one, avoiding reuse or attempts at rebuilding the original. Inspect the ends of the oil pump driveshaft and the plastic collar that retains it; if there are signs of wear or if the collar is cracked or missing, replace the shaft with a new one. The plastic collar centers the oil pump driveshaft over the oil pump shaft, and its absence can lead to damage. A new plastic collar is typically included with a new oil pump or driveshaft. Prime the pump by pouring clean engine oil into the pick-up screen while turning the pump driveshaft. For installation, align the flat on the driveshaft with the slot in the oil pump shaft, ensuring the plastic collar is fitted over the joint, then install the oil pump and driveshaft assembly into the block, engaging the upper end of the driveshaft into the oil pump drive. Finally, install the pump mounting bolt and tighten it to the specified torque, with the remainder of the assembly following the reverse order of removal.