We towed our Elite II with a 2019 Duramax diesel 6.5 ft bed over the Beartooth pass in Sept. of 2019 without issue. I wont lie, I experienced some anxiety in anticipation of the trip and my blood pressure may have been elevated a tad as we motored on, but it was worth it. We set the pace we were comfortable with, pulled over to enjoy the scenery and to let others pass at several of numerous overlooks. I must admit that having an engine brake makes mountain travel much easier. We were not the longest rig on the pass. I would suggest to be on the pass earlier in the day to avoid the masses.