Timing chain
 

Hi I have a 01 silverado 2500hd, 6.0 gas. I am trying to put in a new timing chain. I ran into a little problem, when I got it all opened up I found the oil pump is located on the crank shaft going down into a tube into the oil pan. I can not get the pump off the tube in the pan to remove and install a new timing chain set. Is there a way to do this? Thanks Larry