hi,,dont drop the pan yet,,if you didnt hear any knocking before you shut it off you probibly broke a oil pump shaft,,mark and pull the dist.,,then pull the oil pump drive shaft by taking a large screwdriver and turning it in reverse to disengauge it from the camshaft drive gear,,pullit up and out,,if the hex end is broke off,, theres your problem,,use a magnet to pull the broken part out of oil pump drive,,,replace and assemble,,,.if you cant pull drive you can pull the intake manifold for beter access,,shouldnt half to ,,even if you pull the pan you still need to pull dist and shaft anyway as they dont come out through the pan anyway,,if shaft is good you have a more serious problem,,,..if very cold there,,you could have water in bottom of pan and it froze,,.pull plug and check,,if so heat pan and drain,,replace oil and run to get oil into lifters and rest of system,,,then find where water came from,,.keep us up on your progress ,,,....rick