They crunch only if you don’t do while the engine is idle.
If you did it carefull with the old PTO’s you could do it also without the clutch.
The I-shift is a manual box, electronic operated, if you switch the PTO in before he is idle you hear them grind.
There is a problem if you have a heavy silocompressor and he cannot start up at freewheel (if you have back pressure) he will give a kind of a bang not so nice.