The electrical signal to the C solenoid is a modulated signal, not just on or off, as your switch applies full pressure, or no pressure to the clutch. You have been driving with the the clutch fully engaged, hence the heavy steering. The bang you heard was the clutch disengaging and the drive line unwinding, as in older 4 wheel drives when you pull them out of engagement.
I would not drive in this mode as tyre scrub would be high.
Harvey.
