96 Intrepid oil pump?

I own a 96 dodge intrepid 3.5 v6 180,000 miles. Has never used, leaked or burned oil. While driving last week what sounded like the oil pump started "rattling or knocking" I checked the oil it read full. Oil light did not come on. I would like to find out what other parts connected to the oil flow could be making this noise. Since the pump cost $245 and about $500 in labor. Could it be the sludge in the motor I have been reading so much about? If it is the oil pump, is there any easier way to change it besides jacking car up and taking off "half" the parts to get to it? I have had this car 3 yrs and this is the first major thing to go wrong. I really hate to give up my car!