electric over air dump valve for spread axle how-to, anyone got one?

Yes it is a dump overinflate. The system has 5 air tanks, you overinflated front axle, while dumping the rear axle.

 

Many of them also have three bags per axle, and can actually get the rear axle off the ground with a loaded trailer.

 

That is correct, most don't have a 3 bag system.

 

This is the Valve I use for dump axles. It is VELVAC Part # 320189. It isn't going to dump super fast but if you know you are coming up on a tight turn or just maneuvering on a jobsite you can hit it ahead of time.



On my truck I have an auxiliary 7Way plug which uses a reversed ground pin so you can't mix the plugs up. Mine is factory wired to a switch on the dash to feed +12V to the center pin.

 

Get yourself a engine fan electric over air solenoid/switch, i use the Horton one. Mount that near what you want to control, plumb air for controls, run wiring to what style plug you want. Then wire switch in cab and run wiring to plug.