Originally Posted by sandawilliams
I hope it will end up closer to the 15.5 once it is broken in. This is the problem I am having with the new hemi. Trailer life did a test with the new truck and reported just 11 MPG solo and 8.? towing only 7000 Lbs. My 2009 5.7 averages 9.3 MPG towing 7200 Lbs. with 1000 Lbs. in the bed. I was hoping to upgrade to the new 2014 but am having reservations on which hemi to purchase.
I have only 840 miles on my 6.4. 4.10 rear end. Too early to tell what the overall average is going to end up. I see you have a 2009 1500 and I can tell you that unless all
your trips are longer, steady-state, your not going to see 15.5 avg with a 2500 HD truck. Your going to be disappointed if you expect 1500 mpg out of a 2500 gasser, but your going to be doubling your payload. If you don't need 3000# of payload and are happy with what your 1500 provides, stay with a 1500. The 6.4 is not available in the 1500 platform.
I'm averaging 13 with mine right now. I traded a 2013 3500 6.7 CTD and it was averaging 15 in the summer, 13 in the winter. I'm pleased so far with the mpg with so little mileage on the truck. This 6.4 will get better mileage than the 5.7 in the 2500/3500 platform. I was only seeing 11 with the 2013 CTD pulling my 6500# travel trailer and that was at 65 mph, but the towing power was effortless. I got 9 towing with the 6.4L on a recent trip. Take a look at the 6.4L forum section here. Good reports there and guys are seeing some fantastic unloaded hwy mileage with the 3.73 rear end for a 2500 gasser. I only wanted 4.10's for the gearing advantage and the hills in my area.
Good Luck with your decision!