In addition to what Hector was saying another element is occuring. The Lift chambers begin to loose pressure gradually not like the norgren that once it gets to that threshold it dumps all at once.

The lift chambers are slowly pulling on thetag lift chains as the aux pressures drop and before the suspension actually drops.

If U ever heard a popping or knuckling sound in the rear when parked its those lift chains pulling on the axle as the psi is going down but before the pressure drops enough to evacuate the air in the bags.

Jim if yours is losing air that quickly it will be good progress early on finding the bigger leaks because a leak that fast should be easy to hear. U need a Prevo guy with a bottle of soapy water to start the process of tightening up that camper.

John what appears to be ALL the air dumping out in the back I think that may not be entirly correct. When this occures go and check the rear air bags and if my guess is correct U will still have drive axle air bag pressure and only the tag bags are empty?