93 100 with a 2.8, has an oil leak at rear of engine, leaking down passenger side and dripping on exhaust. Was told that it was a head gasket leak, but it appears to be coming from above that point. Possibly valley pan, are they prone to leaks??
Also going to replace TB, water pump,tensioner, etc. What is involved, and is there anything odd that I should know about. I purchased the crank lock and cam gear lock bar.

 

Pulled the intake today and the valley pan is the culpert