Secondary air tank drains fast, but only on the highway

I was hooked to a load going through our terminal to get into a loaner, but after checking out two loaners beat to hell and being tired of dragging my #### from one truck to another, I decided to cash in all the "favors" I've done for dispatch to keep revenue high and said "hey can I just stick with this truck, do you have anyone else to run this drop in the morning" and they were cool with it.

 

Hey we're they able to find the problem? I'm having the same issue

 

The air was being used by the automatic transmission. The clutch was replaced and this solved the problem.