2011 Volvo loosing air

how far down does it leak that fast? ishift? they can leak from the flywheel housing. ishift air tank may have a pressure protection valve on it. get out the soapy water and start searching. air dryer and valve exhaust ports can be quiet leaks.

 

Check for a message 'Transmission low air supply'.
If this message exist, most probably is a trans leak.
Trans air tank, check valve, inside the transmission.
If it's an inside leak, it is very hard to hear.
Like a clutch actuator leak.
Easy to test by raising the air pressure, shutdown the engine, disconnect the air line supplying the trans and check the pressure back in an hour.
For an inside leak, the trans have to be dropped.
Time consuming and expensive.
They usually start to leak on or before 750k miles.
I would check everything else, leaving the trans at the end.
If you decide to drop the trans, be ready to change the clutch, the actuator, the clutch plate (may be turned over and machined) and the plate bearing.
Ask the tech to be careful with the internal harness, when they remove the trans cover.
It can be easily damaged.

 

Is the leak inside the transmission or not sure yet?

 

The check valve that prevents the transmission air tank to be drain needs to be checked first.
It's unidirectional and if it's leaking back it needs to be replaced.

 

Between the F (secondary) air tank and the transmission air tank.
Close to the transmission air tank.
Check post#5 on the next link:
VOLVO D13 - I-shift transmission air leak
Then read the whole thread.
Edit: NazRiza is a good tech located in Chicago area.
Add: I-Shift service bulletin link.
I Shift Transmission [9n0kpro2kk4v]