There is a diesel supplement to your owners manual. Google search will provide the Ram supplement. Do not use additives.
Use the Stratapore fuel filters as you want the extra fine pore size. Change according to the manual, DO NOT RUN THEM LONGER. I buy them at Genos garage. If ever adding anti freeze use the one recommended by the owners manual which is probably OAT for 2013. Manual has a warning about universal coolants.
Do not idle it long and use the idle bump up feature. Dont lug it all the time, let it cook so it doesn't get sooted up. I often run in 5th gear instead of letting it constantly shift up and down. TH will often keep it in 5th but may not act the way you want at lower speeds so sometimes TH works for me sometimes it doesn't, it all depends on the terrain. I often run in 5th at 1800 rpm. 22,000 lbs
It may say to grease the front drive shaft but you probably wont find fittings on it.
I try to drain a little fuel off the filters between changes. It's not so messy doing the front filter if you lengthen the drain hose and fold it up out of the way when done with it.
I buy fuel at busy big name or truck stops. I also buy DEF at truck stops or Walmart.
Your truck was shipped with synthetic oil because it's mandatory for cold weather starting. So run syn if in cold climate. I run Shell Rotella Triple T up to 10,000 miles. Genos has a write up on it and other brands. If you are in cold temps and have the dealer change it be sure the oil part number is for synthetic.
Dont over service the air filter. 2013 should have a computer restriction indicator. My son used a Fram air filter and keeps getting an air filter restriction indication in damp conditions. Ill go with oem when it's time. Yes, you can change the air filter too much.
Even The heavy duty As69RC trans wants a somewhat early fluid change at 30,000. I'm running Mobil 3309.