Hello, I have a 06 3500 express long wheel base van and I like it I am a chevy man the only problems I am having is it is running rich and smoking after long periods of idle time but that has nothing to do with the van itself its the engine and would have the same problem in a pick-up if my engine went in a pick-up not the van, I love the torque it has, even though its cut back to 460 foot pounds. I never haul over my gross which is 9600 lbs and I don't tow with it, it wil handle any mountain east of the mississippi with out even comming out of overdrive of corse thats at 64 mph thats as fast I drive it!! "fuel economy". I drive about 10,000 miles a month 70% highway 25% rural, and 5% traffic trans seems to hold up well and runs cool it has a 4L85e in it with a extra trans cooler out front my old van had a 5.7 gasser in it, it was a 2000 3500 ext express van and had a 4L80e in it and I got 347,00 out of the trans before rebuild and got rid of the van at 649,000 and trans was still running good, And I do belive in using syn fluids for everything AMSOIL is all I run. Another guy I run with has a 2006 3500 express cut-a-way with a 14 foot box and 12,300 gvw it has dual wheels of corse, he has about 130,000 on it, same d-max I got and he has not had 1 problem with anything on it he gets about 15 mpg at highway speed fully loaded I don't know what he gets empty, is box is 14 foot long by 96 inchs wide by 78 inchs tall hope this helps you out forgot to add my van gets 22.50 to 24.00 mpg empty and 19.00 to 20.00 loaded highway, city is about 15 to 18 mpg loaded or empty GO WITH THE D-MAX!!!!!!!!!!!!!!!