My towing experience (Hemi and 6k lb trailer)
I used the mighty JGC to tow a 19' enclosed trailer from CA to WA, a total of 1,115 miles. There were a few mountains to cross (3k feet or more) and plenty of up hillls to work the Hemi. I did one tank on board computer vs manual calculation for mpg and they were close enough that I only used the EVIC after that.
2010 WK 5.7 Hemi
Tow Package IV
daily temps around 65-70 degrees F
tow haul mode
target speed 60-65 mph
19' enclosed trailer (estimated 6-6.5k lbs loaded, unknown tongue weight)
EAZ-lift 800lb weight distribution hitch w/sway control
Hayes brake controller
I got around 7.5 mpg the first day which was mostly flat. I suspect I had a head wind as she did not go into 5th gear much at my target speed of 60-65. The second day I got better mpg and ended up at 8.7 overall. (both days combined) I was able to ride in 5th most of the 2nd day at my target speed and got better mpg. (and I did most of the hills the second day)
Tow/haul mode was on pretty much the whole time. I turned it off if I was going down a long hill that wasn't too steep to allow the gas saver mode to come on and let the trans drop a few hundred rpm. It did stay on for steep hills tho since a nice feature of tow/haul I noticed was it downshifts the trans if ya get too much of a head of steam rolling down a big hill.
I was very pleased overall with the JGC's ability to tow that load. The Hemi is plenty capable and did not want for torque or power. The weight of the load vs the vehicle is starting to be something, but it had pretty good manners with the WD hitch. I towed it around 30 miles w/o the WD hitch before deciding to spring for the upgraded hitch. Money well spent!!
The trans fluid is still a good color after the trip, but I could smell the trans heat every time I stopped. The engine temp was solid and barely moved over normal operating temp on a steep up hill.
North Edition: 25X - 5.7L V8 Hemi - QuadraDrive II 4X4 - Skid Plate Group - Tow Package IV - Uconnect - 18" Chrome Wheels - DVD Entertainment System