That's our st trk/red COE. With a 5th wheel it did a decent job pulling an oversize load Miami to Cleveland @ 96,000# . I yanked the 5th wheel off and bolted the box on.Well under 40' with 108" of combined sleeper space. NTC 370/435 w 10 spd 3.55 rears. Staying in the mid 10's mpg with a high of...