A quick search regarding a noise like that on 3.3 brings up lots of cases where a clogged oil way in the head caused loud lifter noise in the back bank which eventually led to serious damage in fairly low mileage engines. I would not ignore it. Maybe try oil flush and high quality synthetic oil. Several reported Chrysler actually replaced engines under warranty when it started with a single very loud lifter/valve train rattle or click.
Last edited by Hate em but keep buying em; 09-05-2011 at 12:35 AM.
Reason: added info