So a customer brought in his truck complaining of a strange noise at idle and when revved up to about 1400-1600 rpm. So we start checking all the pulleys on the motor, thay all check out fine. So we pull the water pump out and everything looks fine. We are stumped so with just the balancer and the water pump reinstalled we start the truck and listen very carefully and the noise is coming from behind the cover. I remove the front cover and this is what I find. The oil pump gear teeth are hammered. Only gear that is messed up. The truck only has 89, 000 miles on it.