Loosing oil in 2016 SD
 

Going for a oil change tomorrow at 7k miles. I just looked at my oil and I’m only in the hash mark on dipstick about 1/3 of the way.
WTF did the other 2/3 of oil go? I have no leaks. Truck is a gasser with 18k miles on it. Yes, I did check the level after last oil change and it was full. Driveway is level

The dip stick doesn't do to the bottom of the pan. That does not indicate you are missing 2/3 of your oil. Maybe a half qrt.

Correct. Guess my post is worded wrong. I think it’s more than 1/2 qt. But regardless, even if it’s 1/2 qt, why would I have lost that much oil in the first place?

Oil doesn't just disappear. It can only go a few places:

• Onto the ground (quite noticeable; common with older vehicles)
• Into the water (head gasket issue; common with older vehicles and overheating)
• Out the exhaust (leaks past piston rings into the combustion chamber, and pushed out the exhaust; you should see blue/white smoke)
• Oil was never there in the first place (meaning it wasn't filled full before)
• You read the dipstick wrong (You filled/checked the oil while on a slope; later checking level/sloped revealed different reading)

Sometimes engines use a little oil. That doesn't seem that out of the ordinary.

1/2 QT in 7,000 miles is not unreasonable when you consider the variables mentioned above. After you change the oil park it on a level place and check it after about an hour, note the level and use as a reference for future checks. I would not lose a lot of sleep over it.
If its the first oil change at 7k most new engines will use a little oil during break in.

This is the internet. The guy could be not pushing the dipstick back in all the way for all we know. Just gotta post up some common things and hope he figures it out.

All of the above, plus the temperature of the oil and how recently it was run can adjust the level. That's why if it's in the hashed area, it's fine.