Yep I don't doubt that for one minute about the air ride, but they need the air ride do to the stiff suspension they run. Spent a lot of time in both FL and Volvo class 8 tractors when I was laid off. Also have to agree 100% on the maintenance of your rig.
I have been asked why I replace items before they break. Well I don't like nor do I want to be sitting along side the road waiting for a tow truck because I was to cheap to fix it before hand. I replaced all the soft brake lines on my truck at 120K. There was nothing wrong with them other than I felt at 120K they needed to be replaced. Same thing with the cab lights, had one gasket fail so I replaced all of them.
Don