My '09 4 door shortbed 4x4 2500 had DPF delete, egr delete and a tuner installed before I bought it.

It NEVER shifts out of 6th pulling a loaded car trailer even on the steepest hills!

Pulling a car trailer with a car and an extra engine in the bed full of parts the 6.7 got 15 mpg. On the highway it always gets over 20 mpg when empty and not towing. Hand calculated!

It weighed 7,500 lbs. crossing the scales at the landfill with me and my son the other day. (He weighs 150 and I weigh 200.)