What would you check first? i have a gusher!
 

2007 H2...never an oil leak until yesterday and its like someone turns on a faucet when the truck is running. Soon after the it is turned off the leak stops. I've considered the rear main seal but that usually starts with a drip and gradually gets worse. This was all of the sudden and it is bad! What would you check first? I see no oil looking down from the top of the motor and it is leaking so bad that it is really hard to pinpoint exactly what area the oil is originating from.

All we are doing is guessing, but I would say, oil pressure sending unit or oil cooler line.

the first thing to do is find out what color or type of said oil is. next step is to go under and look for said oil.