If you re-gear to something numerically lower, (which might be fun to find) you are also going to reduce the vehicles tow capability... right now, you are pushing it anyway. Max trailer weight for you with those gears, and assuming the 5.7, is 7100 pounds..... Not sure there is a heck of a lot you can do there.... aside from drive slower.......

 

You should have a 3500 series truck for towing something like that imho.Just because you can tow 7000 lbs doesn't necessarily mean you should.That is going to be very hard on the engine and transmission for towing long distances.There isn't enough reserve capacity there.

 

here is a link to the towing guide
https://www.ramtrucks.com/assets/tow...ing_charts.pdf

Your truck tow limit is around 8000 lbs (8170 lbs for crew cab short box 4x2 and 8000 lbs for the 4x4). Based on the weight you are towing and the RPMs/speeds shown, looks like you have the 33" tires. So you are towing in 5th gear all the time and your truck is not going into 6th (1:1). If you were to change to 3:92 gears, your limit would go up about 2000 lbs and you would probably be able to get into 6th gear, however, the RPMs would be about the same as with the 3:21 in 5th. I doubt you would see any improvement. Less stress on the drive-train maybe but about the same MPGs. I have a 2017 Big Horn CC 4x4 with the 3:21 and tow a single axle TT that weights just under 4000 lbs. I regularly get 10-11 MPG towing and as low as 8.5 with strong head winds and as high as 12-13 with tail winds.

 

for better mpg...how about slowing down 70mph!!!! ru kidding
not worth it to change out the frt and rear diff...the next ratio drop ain't gonna make a big mpg gain but you need that gearing to tow that weight. No idea if you have the 6 speed or 8 speed?

Being an engineer you know the engineers who built it already have it at it best. You are at the limit of the vehicle...get a bigger truck or put up with it. And if you at some time buy another truck...Don't get a ecodiesel...wait until its proven itself...it hasn't so far.

best your gonna get with that truck in the current setup is 8 to 10mpg towing that load.

 

Yes i second slow down,,,, anything basically above 55 mph when towing will kill mpg., I usually pull my trailers at 100 kmh or about 60 mph max,,, as for 7000 pounds needing a 3500 series truck,,, lets get real,,,, a 3500 series truck is rated for 30,000 pounds,,, I hauled RV camper for just over 2 years now , with my Ram 2500 diesel,,, I know not the same truck and that truck was legally licensed for 21,000 GVCW,, so truck weighed in at around 7500 empty, so that left me 13,500 for a trailer. Now when a 1500 series truck cant pull a 7000 pound trailer something is drastically wrong, considering most 1500 now are said to be able to pull at least a 10,000 or more trailer,,, i believe the ford is rated for 11,000 for a F150

All i can say is if his trailer is too much for his truck, I better sell my Dodges and move on to a ford or chevy

 

Ahh,didn't know it had the 5.7 hemi and 8HP70 trans.Probably still pulling more weight than calculated without using a freight scale.

 

7000lbs is almost 2000lbs more than the weight of the truck...on a bumper pull for a 1500 the limit is on the suspension. my 2500 basically uses the same trans and engine as a 1500 but it tows so much better. pulling that weight on a semi floating axle...no thanks. I prefer to have more truck than I need. mpg is no better 8-10. efficiency towing, diesel is the only option. but with the diesel...the money you save on fuel...you pay back on service.

 

I agree with others, nothing can really be done, you just need to slow down if you want better mpg. My box trailer fully loaded is around 6200 and the best I get is 11 mpg. And that is always on secondary roads where I do not cross 60mph. On the highway, with the high wind resistance and higher speed of 65, I get 7-8mpg. That's a 5.7, 6 speed, 3.55 gears. The best mpg with my hemi is around 2000rpm. With towing, it's hard to keep it that low so mpg will suffer as a result. For the few times I do it, I just deal with it. Look at this way, 20-30 years ago, that was the best mpg available when completely empty!

 

I would get between 6-8 pulling our TT , about the same weight , 2009 Hemi crew cab 3;21 rear axle
slow down , what ever you get on in town mpg --- cut it in half
my 2009 turned 391,000 today