Replacing an oil pump on 2003 Chevrolet Express 3500

Need to replace oil pump in 2003 3500 s express van 6.0 Prob has already been diagnosed How big of a job is it to get the pan off?

Asked by for the 2003 Chevrolet Express 3500
6.0 motor timing cover and oil pan has to come off oil pump is on front of crank shaft oil pan may not have to come off if it dont have no oil pressure at all better rebuild motor ck with manual gagage