New Rebel owner here with the ED

[Katoom]

Ok so I just couldn't hele myself after my brother in law bought a '23 RAM Laramie with the ED motor I knew I just had to have one after I drove his. Now that said I've always LOVED the Rebel trim so the hunt was on for one and I was able to find a '20 with 65k miles on it and in very very nice condition. Now, that all said I'm stumped as to why his gets 30mpg down the hwy and I just eeek out 24 MPG? Maybe he's got the 3.21 gears I dunno but I'm quite certain my Rebel has the 3.92 gears. Don't get me wrong I am pretty thrilled with this truck but part of the reason I made the jump was for the MPGs. I came from a super low mileage '19 F250 with the 6.2L and it was great but crazy thirsty and was a PITA to drive around town due to the nature of it being a big SD truck. I do have some other concerns with this rig as it's been owned by 6 others but never been wrecked so that's good and appears to have been taken care of just find it suspicious that so many before me didn't like it, or maybe it's plagued with issues that I'm about to find out about, sure hope not..
Anyhow, should this truck be getting better than 24mpg on the hwy averaging 70mpgs or does that sound about right, keep in mind I live at 4500' elevation in UT so there's parasitic loss from that otherwise should be the same as any other truck.
One last thing, I have 65K miles like I mentioned and I don't know when the tranny was last serviced, should this be something I have done right away or can I drive it safely for a while longer before taking it in?

 

[1BADRAMLIMITED]

a loss of 6 mpg could be a multitude of things. i bought my 19' 5.7 non et and had trash mpg. after i got my cracked manifolds replaced, new air filter, new spark plugs, alignment and new tires ( i went up to 35's) i now get better mpg than prior (33's tires). i also had the injectors cleaned.

 

[Alter Ego Trip]

Changing from Ford to Ram usually cures ED not causes it. 😆

 

[TSL]

I have a '22 Rebel with the ED motor. I'm just approaching 17k miles on it ( I obviously don't drive it a whole lot ! mostly for camping trips actually )
Anyway, I average about 22mpg in mixed driving, in town and on rural twisty 2-lane country roads. On the highway I will see up to 26mpg, but never get near the 30 I do see quoted by Laramie owners ( and my neighbor in a GMC Sierra AT4 trim with the baby Duramax, he gets 30 often )
I think the Rebel is just a heavier truck, it has factory lift so it sits higher and that is a lot to do with it. Perhaps the 3.92 gears too.
I also two a pop-up camper, it's on the heavier side for pop-ups, loaded its about 3600 to 3800 lbs. I get 20mpg with the Rebel on average towing the camper, including mountain grades. ( Obviously not 20 going up the grades, but the average overall for a trip is around 20 when towing )