Rear Main Seal on the Crank shaft is leaking if it is oil. If it is transmission fluid, the pump seal on the transmission or the Torque Converter is leaking.

 

It is oil. Thank you bro man. Now to change that I take off the oil pan?

 

Depending on the severity of the leak, yes your truck will keep running fine as long as you keep the oil level in spec. If it is leaking so bad that you make a mess everywhere you go, then you will have to get after that rear main seal quickly.

 

Thank you for your response.
How long have you had your ride?

 

Here's the bad news. You have to remove the transmission to get at that seal. It is doable DIY, but it's not easy.
There are products available as oil additives that are engineered to swell older seals and rejuvenate them. Sometimes it helps, sometimes not. Won't hurt.
My 2010 has 103k on it and has a minor leak similar to yours. I occasionally pull that large plug and clean up the area. Mine is not enough to drip, just weeps. I run mobil 1 high mileage and it has some of those additives. As long as it doesn't make me clean the driveway, I'll keep it as is. Once I need the power washer, I'll have it addressed.

 

the auto parts store I ordered from sent a transfer case adapter o ring.
any experience changing those out?

 

I do not have experience with that. Hopefully someone who does will chime in.