The water pumps on these engines are kinda tricky.
Drain Coolant, Remove the shunt line(hard metal line), Remove the line on the bottom of the water pump going to the Air Compressor. Remove the metal elbow and hose going to the EGR cooler, Be carefull, keep a pan under it, you will lose alot of antifreeze here.
Remove all the fittings going into the water pump(this makes it easier to wiggle out)
Remove the 3 bolts holding the water pump in place, 2 go through the gear case, and 1 goes through the back of it into the gear case. the ones going through the gear case are 10mm 12pt, and the back one I think is a 15mm 6pt bolt.
There are 3 bolts holding it on, one faces toward the back, and 2 go through the front of the gear case.
I have managed to do them without pulling the EGR cooler off, I just take out the 4 EGR cooler mounting bolts after getting all the other hoses off to wiggle the water pump out, You can pry the EGR cooler back a little bit to get it out. It will come out.
NOTE: If the water pump is leaking from the plastic cover on the back of the water pump, there is an O-ring behind the cover, THIS CAN BE REPLACED WITHOUT PULLING THE WATER PUMP. We do this under warranty alot. And it can be purchased from your nearest Detroit Dealer.
I would have provided the direct service manual instructions, but mine are more detailed. The service manual says drain the coolant and remove the 3 bolts hold it on. HAHA, it is not that easy.
My suggestion to you also is to replace the blue hoses, they leak eventually.