Can anyone tell me why this Dana 44 is leaking in this area? What is this plug for? 1978 Ford F150 Dana 44 front is this some type of plug?

Thank you

Carrot66

 

looks like a plug weld to hold the axle tube in... is it metal on the inside the hole?

If so the you could just clean it off and place some more weld over the exiting plug weld. never seen that before though..

 

It's a pretty common leak point if the axle has been beaten on. The axle tube is pressed in place, then the weld is just kind of a keeper so it doesn't move too far. The cast iron can stretch a bit if it's severely stressed, and so the oil will start leaking out.
Don't weld without following proper procedures for cast iron, and take the weight off the axle beforehand.

 

Thanks for the information. This truck has been driven on the street since 1995. I was replacing clutch linkage when I noticed the leak. There was quite a bit of gooey dirt around the hole preventing the leak from showing up on the garage floor.

Carrot66

 

forgot about cast iron welding... probably want to drain the differential as well since gear oil doesn't react to fire very well! ask me how I know!!!

of course you could clean it off and stuff some JB weld putty in there for awhile if you need to keep your garage clean...