To sort things out some...Look real close at air pressure gauge...does your air pressure gauge have one or 2 needles? If you have 2 needles, one needle shows total amount of psi air in system and the other needle is the amount of pressure being applied to system.
If so...when fully charged up with air(if you can) ...apply brake, then does one needle keep going down? if so you could have air leak or spec of dirt stuck in a valve somewhere. Or if you're in cold climate right now, rubber in a valve is stuck (valve is not sealing air tight) because you have moisture in air system somewhere. Or maybe you drained your system and left valve open and leaking air. If any above applies problem is in air system not trans problem. Above is based on what I'm used to in air brake system.
( :)P.S. Ha, HA, Ha ...if you're on the clock right now...call your dispatch, tell them air is froze up. Buy 4 cups of coffee. Pour 2 into air system and 2 inside yourself. Both systems will warm up. Then after thawing, drain air brake system to get out water, then drain yourself later:))
2003 Majestic 23P... Northwest travel machine
2013 Arctic Fox 25W... Wife "doll house" for longer snowbird trips
2001 "The Mighty Dodge"... tow vehicle for "doll house"
