Cam phazers.....If you stick your ear in the passenger front wheel well you'll hear it better. It's not a bad job, maybe 4 hours? You need to take both valve covers off and mark the timing chains before removing the old phazers. You also need a special tool to jam down between the front covers to keep the chain from falling back in. You'll need an A/C machine to recover the R-134 because you need to removed one of the lines from the accumulator to get the passenger side valve cover off. Pretty straight forward, just a lot of B/S to do it....