RAM 2500 6.4L Towing Observations

jmtandem wrote:

I pulled a 12k 5er with a 5.9L Cummins in a 2007 3500 SRW and then the same 5er with a 2014 Ram 2500 with the 6.4L Hemi. The Cummins got 10-12 mpg and the 6.4L Hemi got 7-9 mpg with the same load.

Exactly, 12,000 pounds is getting near the end of the performance envelope for the 6.4 and only about half way for the newer diesels. If you calculate the difference between say 11 mpg and 8 that are the mid points of your experience it is easy to see that the diesel is at least percentagewise substantially more fuel efficient under load.

I have heard nothing negative about the 6.4 and if I wanted a truck to go grocery getting, take short trips, tow almost never or a very small trailer then the 6.4 might make sense to me. One of the biggest problems of all normally aspired gas engines is altitude. In the mountains the power loses about 2.5 percent per 1000 feet altitude. The turbocharge diesel can develop sea level power up to around 12,000 feet. It makes a difference towing a heavy load up the hill.

Going to have to disagree on this statement. I tow an 11995 GVWR fifth wheel with the same truck/year as the OP. I get the same mileage as reported by IB516. While your comments regarding altitude may be true, the 6.4 is very capable of towing heavier loads - it just makes it's power at higher rpms. Mine runs at 25 - 30 K rpms in the flats in tow/haul mode and downshifts on overpasses. I run at 65 mph in cruise control. This doesn't bother some people and it is perfectly normal, but it tires me out. The transmission has me wanting for better as it hesitates and slams into gear when changing. Have not towed in the mountains, but after towing this weight with this truck, I don't plan to for that reason only. I'm currently shopping for a one ton diesel. I'm sure this won't be an issue for the OP though as I'm sure I'd be just as happy as him if towing my old TT.

Your comments regarding grocery getting and infrequent towing are trolling at most and most likely stem from ignorance - the truck in question is a very capable towing platform both at the weight the OP is towing and the weight I'm towing. You had some valid points which were diminished by these comments.