Oil weight
 

I just bought a 2006 6.0 powerstroke. 128k miles. I'm getting ready to do my first oil change and I'm not sure what weight to use. I live in Missouri, our summers are usually anywhere from 80-95 degrees, only a few days of 100 degrees and our winters are usually below 32 degrees but rarely below 0. I pull a trailer everyday and fully loaded it weighs about 2,200 lbs. should I use 15w40 or 5w40 synthetic? Does brand make a difference? Does filter brand make a difference? How long do I go between oil changes? Im a little worried about usually synthetic because I've heard they cause leaks. Thanks!

I use 15w40, as for brand i use delo, del-vac or rotella which ever one is on sale, i change my oil every 5,000 miles.

1) Use OEM oil filters, anything less will cost you more in the long run. WalMart sells them cheap.
2) Synthetics causing oil leaks is old school mentality. LONG ago is was true due to the gasket materials not being compatible.
3) Get any weight you want to run as long as it's spec'd for a diesel
4) 5k to 7500k miles is a good interval. Spend what you can afford.