What needs to happen to change rear engine seal and/or change oilpan gasket

Thank you Hal.The oilpan has very little clearance as this is a 4x4 dually the crossmember is very tight to the pan.What is the likelyhood of the leak coming from the pan itself?The oil is coming from the rear of the engine and I pulled the cover off the torque converter it is difficult to say that it is definetly coming from the seal or the pan.

Clean it up with brake clean and monitor. If it's the seal you'll have oil slung everywhere in front of the flexplate. Remember to replace the flexplate bolts. Looks like exhaust can stay in place...