back in early '02 I had Air Lift Air Bags with on-board compressor installed on our former '02 Chevy 3500 .... the compressor was mounted to the truck's frame ... we used that vehicle mostly for towing various trailers and the compressor worked well in that location ... I sold that truck July 31, 2007 with just over 150,000 miles on it and know for a fact that compressor is still working .... if I was going to use the truck off road or in mud, I'd of most likely had it installed under the hood ... hope this helps
Jim