It appears to be a fuel leak. The incident happened less than 200 miles after having a dealer perform the NHTSA recall 22V-406, FCA recall Z46. The truck caught fire while pulling a travel trailer. The only way we were aware of it was a passing motorist saw flames shooting out from under the right side. As soon as we pulled over the truck immediately filled with smoke and the fire spread as the fuel puddled below the truck. Chrysler sent an inspector to look at the truck, not enough of the engine, passenger cabin, or front of the truck was left to make a conclusive cause. There was no indication we had an issue and if not for the fortunate timing of the passing motorist this could have turned out much worse. I was relating this story in a restaurant to my nephew when a passing waiter asked if it was a ECO diesel and I said yes, he related his story which was identical including the recall. I attempted to put out the fire with a fire extinguisher we kept in the truck but it was too big by the time we pulled over. We were traveling at less than 50MPH stop and go traffic which had just started moving.