I have a 2018 international 4300 series. The DEF bulkhead sensor went out a month ago. The only thing international will tell me it's on back order. This is completely unacceptable. To my fellow tow operators in the industry beware!! It's bad enough dealing with the dealership alone but international does not back their product or stand behind it. I speak with experience this is our third international and all three from the dealer to the product have been crap. Third time's the charm. They have forgot about the working man.