It will sound loud at "idle" (bike not moving). There is a slight pocket of air but nothing where the coolant system is leaking.
The bike will auto shut off once the pack is fully charged. The instructions are simple and exist in your manual and on the forums in a post (search lol)
1. Plug charger in to DCCP port
2. Hit run switch to 'ON'
3. Confirm GCFI (yellow box) button is pushed.
4. Bike should acknowledge charger and start charging process
5. Key bike to 'OFF' (will turn off screen)
Then bike charging will turn off once charging is done.
If the pump is noisy, it's likely cavitating. There is air in the system. Remove the filler cap and add coolant, 50/50 antifreeze. Turn the key on with the cap still off and add more coolant until it is full to the top. Reinstall the cap, follow the torque recommendation which should be written on the cap.
Both of our MXR's I had to add a little coolant a few times until all the air was worked out of the system. I'd be surprised if your bike did not have some air in it's system as well.