What you guys think? Just oil pan gasket needing replaced?

 

Probably.

 

Rear main seal is another good possibility. Clean it all up then see where the leak originates.

 

I have the exact same set up. '97 Dakota with the 3.9. 98K on the truck but 65K on the engine. My valve covers were leaking pretty bad. When I got the truck, I did a tune up with cap, rotor, plugs and plug wires. I replaced the valve cover gaskets while I was in there and now it doesn't leak or burn any oil at all.

Otherwise I'd put some oil based dye in the oil and see where the leak is.

 

Also check oil pressure sensor too.Hopefully its just that or the pan gasket.It was a pita to get to my rear seals- to replace .And engine had to be jacked up to get to it. Its tricky. changing the pan gasket if the pan cant drop too much, as it is ...
Clean it up an try the dye method to find where its coming from .

 

Oil sending unit is a good call. Mine wasn't leaking on the Dakota but when I tore my 5.9 in the Ram down for a major tune up, it was seeping pretty badly. It's right next to the distributor. It wasn't too bad on the Ram as I had the intake off for a plenum repair, but it's buried in back and with the intake in place, you can't see it until you climb over the engine.