Remove the oil pan and unbolt the oil pump, lowering it from the engine; the oil pump driveshaft will come out with the pump, which is a rod with a flat-sided portion at each end. If the pump is defective, replace it with a new one, avoiding reuse or attempts to rebuild the original, and inspect the ends of the oil pump driveshaft along with the plastic collar that retains the driveshaft to the oil pump if applicable. Prime the pump by pouring clean engine oil into the pick-up screen while turning the pump driveshaft. To install the pump, align the flat on the driveshaft with the slot in the oil pump shaft, ensuring any plastic collar is fitted over the oil pump-to-oil pump driveshaft joint, then install the oil pump and driveshaft assembly into the block while engaging the upper end of the oil pump driveshaft into the oil pump drive. Finally, install the pump mounting bolt and tighten it to the specified torque, completing the installation in reverse order of removal.