Towed our 5th wheel for 1st time last week with our 2016 RAM 3500 dually we purchased a few months back. I traded in a 2013 RAM 3500 SRW because our new 5th wheel exceeded the towing limits of our prior truck. When accelerating from a complete stop or depressing the throttle to maintain speed on a hill, the engine knocks. This sounds similar to how gas engines ping when the fuel detonates instead of burns. The engine only does this under heavy load. My prior truck never did this, even under similar load conditions. It's basically the same Cummins engine. What gives? Have any of you experienced this? What was the cause and how did you address it? Thanks.