05 2500 hd tranny fluid change

[Larry S]

I have an 05 2500 Hd 6.0 vortec auto. The truck only has 42,000 miles. I pull a 30 ft camper with a trailer hooked to it w atvs thru the n ga mtns alot thru the summer. Its some hard pulls, so I was thinking about changing the tranny fluid. I was planning to do it myself, but I'm kinda busy so I called "stealership" and got a quote. They said around $225. My question is WHY IS IT SO EXPENSIVE? I usually work on my own stuff and am wondering, if it cost that much, is there "something Im missing."