Help wanted!! I am new here and don’t know everything there is to know about how to work on these trucks. I just got the truck for a pretty good deal and it runs and drives. Not good but it drives. Shifts fine. My question is, can anyone please identify what this whole is next to my oil pan? It goes all the way through. It looks like oil is dumping from that area but I don’t know. Can somebody please help. I just noticed this today. While is on driver side of truck.

 

I don't think it goes anywhere. I suspect it is for an alignment jig on the assembly line, but, not 100% on that.

Stick something up in there, it *should* be just a blind hole.

 

That's just a machined boss on the block. I think it was used to lower the drivetrain assembly into position when the truck was built.

From the pictures I'd say either your oil pan gasket is leaking (not too bad to fix) or your rear seal is leaking. (A major pain to replace as either the engine or transmission has to come out.) Before you start pulling parts, get a UV dye test kit and a bottle of dye for oil based systems. The kit comes with yellow safety glasses and a black light source, usually a pen light. That intense UV light can damage your eyes quick, hence the YELLOW safety glasses. Normal clear ones are out of the question. Pour the dye in and drive it around a bit. After 20 miles or so, less if the leak is severe, look underneath and shine the black light on the leak. It will spread out from the leak. It will show up as an intense green streak pointing to the leak. It's not cheap but not expensive either. This will save you some major time. If for instance, it's leaking out the sides of the pan, you just need to drop the pan, clean it up and put a new gasket on the pan and reinstall.