Diesel Bombers - No Oil Pressure

So I run a shop. Guy i work for has 4 dodge 2500s and i have one guy who comes in just for me to work on them. 3 of them have the 24 valves and the other two are the 12 valve. Any way my customer comes in last week for me to replace his turbo, front timing cover/crank seal, and ac compressor. I always use a sanding disk with a die grinder to clean off all the old rtv. Well he said that his turbo went out in Texas and drove it all the way back here to northern Indiana. His oil pressure was at 43psi when he pulled it into the shop. Well i get the compressor and seal changed out. I go to prime the turbo and find that there is no oil pressure anywhere in the motor. Now through thread i have read here it could be a few diffrent things. One thing that we are hoping is that the pickup tube is cracked or broken. So i loosen up the motor mount bolts but cant get the engine to release from them. Can anyone help me? And Any ideas on the oil pressure?