I've got a 2006 1500 5.3 with 140k miles. Just today I noticed the oil pressure dropped down to zero so I stopped, shut it off and check the oil. Oil was full and looked clean. I change the oil every 3k miles. Well I stopped for lunch and about 30 mins later I started it back up and it started ticking really loud so I shut it off and let it sit. Could this be a bad oil pump or rods? I have to drive 3 hours home come Thursday. Any help would be appreciated.