Air ride question

[Nobby]

I have a couple questions. 1st , If I put a schrader valve in the airline from the pump to the tank(in case I have to fill tank manually) will it backfeed into the pump and damage it? 2nd, My digital pressure gauge is going nuts ,it constantly reads different pressure.Has this happen to anyone? One more,when you haul your truck on a car hauler do you guys air it out are leave a little air in.I was just wondering if it was hard on the suspension with the truck sitting on the snubbers because when I'm hauling I don't slow down for bumps