2005 Yukon XL 2500 4wd SLT. Engine oil pressure guage recently maxed out.

Thank you, Mark. The pressure only went to 80...maybe just a hair past the line....certainly not 'way past 80'. I'm inclined to just try replacing the pressure sender. My logic is this: a new sender is about $80 and a tester is about $50. If replacing the sender isn't the solution, then I need to take the truck in to a shop for the oil pump replacement. So either way I'm out at least $50 and the $30 difference is worth it to not have to access the sender unit a second time. You've been very helpful. Oh...on my 6.0l, is the sender on the firewall end of the engine like it is on the 5.3l engine?