BTW, the shroud is a pain to get off. It's actually in two halves; Upper and lower sections. I had to bust off the snaps or fasteners to get them apart. When putting them back together, black zip ties worked really nice. You will only need to remove the upper shroud section.

 

I have the same 3500,year and engine in a cargo van that sat 2 years with a blown rear end till i could have it fixed. Difference from your photos is that I have only 2 a/c lines crossing the shroud where yours looks to be 4. I've had to change the clutch fan 3-4 times over the years and had to deal with the shroud but for the life of me can't recall the trick, I'm thinking (as i went out and looked at it) that if you take off the lower half you can finagle the top to come out the bottom... or at least get it around enough to give you room to see in there n work without disconnecting lower radiator lines, obviously you have 2 extra lines up top but maybe that might help you... just be careful not to drag it against the radiator.
At that point I agree with "funair" and check to make sure it's not the bypass/thermostat housing that is leaking first unless you know for sure it is the waterpump. Mine had a slight leak from there after sitting so long I wonder why? I could see from underneath, a trail of antifreeze on the engine front from that area. Never pin pointed it but I'm quite certain it's at the housing... it never made a puddle to the ground and eventually must have sealed up. I'm sure that will be a future project but for now she holds fluid and runs.
Thanks to the guys on this forum n thread I've learned a lot n the old van has been running pretty darned good

 

The B3500 Ram Van wagon seats 12- or 15-passengers. Thus, it has a Denso combi AC-heater in the rear HVAC unit. Those 2 extra AC lines go to the very back of the van.

If the water pump is only leaking from a black tube and hose, then the water pump is fine. There is an o-ring that sits at the end of this tube that fits snugly into the water pump. Replacing this $1 o-ring is by far cheaper than the tear down of the cooling loop and replacing the water pump.

 

Thanks for that info Stev, we must have been responding about the same time. Had no intention of stepping on toes, I just had a thought about the shroud and what I have experienced n thought to share it, the tech stuff is your talent and it's appreciated.