Should I get the extended service plan

The reality is what you will likely experience is repairs on items not covered by that warranty. Engine gaskets, alternator and power steering pump, and items other than "internally lubricated" engine parts. Likewise with the transmission. Having said that, you own a 5 year old heavy duty vehicle with 113,000 miles on the clock. It would be very tempting to purchase. Before you do, read and understand the actual policy, not the sales brochure. Many times you have significant requirements to get them to pay. Often you are responsible to take it to their repair facility which can be hundreds, if not thousands, of miles away. A wrecker bill could far exceed the cost of repair. Also, understand this is an insurance policy, not a warranty. Are in a financial position to pay for a repair that may cost several thousand? Or if you had to make a several thousand dollar repair would that put your RV out of service until you could save up that money? Remember you never insure anything that you can easily replace yourself. That is why you buy insurance for your house but not your toaster!