do some research through the Ecodiesel subforum. They have had their share of issues. The carfax will only tell you maintenance records (if they were shared by the business) and any wrecks. Good luck, hope you are getting a great deal on it. I've read enough on them that would make me think...
You will have no issues switching. In fact, you could change with synthetic one time and go back to regular oil if you wanted. But don't mix two different types. Just go with what Ram recommends for the truck. That is the main thing, stay with the weight they recommend.
I'm not sure exactly what you mean, but I assume you mean the engine is holding higher RPM's to keep the truck from coasting down a hill. Mine does this as has my last 3 vehicles. It lets the engine do the braking so you don't overheat your brakes. It's actually for safety, if this is what...
1. etorque (if she's used to the start / stop).
2. 20" better ride and cheaper tires
3. steps - absolutely needed for my wife to get in the truck.
4. I would stay away from the 12" screen, still seems to have quality issues.
I had a 17 3.6 3.55 RCSB with 2wd (Express model). I towed a small uhaul a couple times and knew it was there, but didn't have any issues. It was rated to tow 7700 lbs. If you get a longer cab, longer bed, higher trim, and / or 4wd, it will be lower because of the added weight to the truck...
Over 75k miles in 17 I got 26 hwy and 21 city. The best I got was 31 on a 400 mile trip, going no more than 65. I got 16 towing a small uhaul trailer.
BTW, I drive the speed limit.
and this was hand calculated by taking mileage between fill ups and dividing by how many gallons I put in.
other than stepping back down to a 1500 Hemi with 3.92 rear end (which would be the best choice for your situation), I would lower the tire pressure to what your door jam calls for (mine shows 60 and 65 for my 2500 Hemi. I'm not sure if there is a lot else you can do.
I would absolutely go with the 3.92.
4k miles is quite a bit and the gas mileage difference is not much.
If you want better gas mileage, just drive the speed limit (or a couple mph slower) and drive smoother.
Good luck, and welcome!
PS, it's much cheaper to add it at the factory than if you...