Anyone towing with 2014 Grand Cherokee/Durango?

I'm towing a 4800 pound/25 foot travel trailer with the new Jeep GC Ecodiesel. Getting around 14 mpg in Colorado, up and down I-70 in to the mountains from Denver.

Plenty of power on the flatlands, but maxed out on the steep grades. Limited to 50 mph from Silverthorne to the Johnson/Eisenhower Tunnel for those who know that stretch. You would never know that was going to happen by the grunt available from a stop and on flatlands. I'm guessing it is due to the lower HP.