Stan, I raise my coach all the time to clear sloped and dipped driveway and business entries and such. I've also dumped air on occasion to get under threatening limbs, esp. given the awning wind sensor cup topside that's in harms way and easily damaged.
Our 06 Monterey has air leveling only, and as such I use the buttons on the HWH computerized leveling panel - the Raise and the Dump buttons. HWH designed them so the coach would stay at the height it was at when you released the button, but at least with the Raise button Monaco jumpered that circuit such that the coach returns to Travel Mode as soon as you take your finger off the button. Their theory in doing so was they didn't want people inadvertently raising their coach and driving off down the highway fully raised, a hazardous scenario on a curve at speed, and as mentioned, a strain on the driveline. At slow speed for short distances like driveway dips it should be okay. As to dumping air to clear branches and such, be aware that having your steering wheel in any position other than straight will likely put front tires into the fenders, an expensive repair.
Our coach is shorter than most and the short driveline is more in jeopardy at full raise because it by necessity will be at a stronger angle. To counter that, Monaco put appropriately snug limiting straps on the rear axle, so though the front of the coach may top out at 4 inches of raise, the rear only goes up about 2 inches; the consequence of that fail safe is that it can effectively lever the hitch actually lower than in Travel Mode. Thus I've learned to estimate when the entire coach is about half raised... 2 inch mark... and release the button, press, release, press, release, to maintain level raise until the hazard is cleared. Kind of a pain, especially if you're trying to concentrate on maneuvering and don't need another distraction. Theoretically the jumpered circuit can be undone, and returned to the original HWH configuration, but I haven't done it yet.
So, just before backing up your drive, hold down the Raise button and perhaps have someone outside watch and clue you in as to your clearance success as you back up, or watch your mirrors against a background for some sense of your height. You'll have to rely on a few attempts and experience, but likely will eventually figure out a successful routine.
Joel
