I just got back from towing my 27' Airstream with my heavily loaded 2015 Silverado 5.3 1500 3.73 from San Diego to (Show Low) White Mountains in AZ via the Salt River Canyon and had to brake hard once with the trailer and once without the trailer on this trip and neither one felt right. First I thought it was because of the heavy load, but when it happened empty without the trailer, it made me wonder if there was an issue. The only other factor was that I had the brake lines flushed just before I took off, so at first it felt a little funny because of that as well. Regardless, I'm scheduled to get the system reprogramed next week before I head up to Idllywild for the weekend. Don't use my brakes much when towing and depend on the Tow Haul mode to keep me safe coming down 6% grades.