I’ve only ever sold fully owned properties.
What’s the procedure or any pain in selling a property you still have a bank mortgage on?
The penalty; is your mortgage fixed or variable?
If variable, the penalty is 3 months interest. Very simple.
If fixed, the penalty is the greater of 3 months interest OR interest rate differential (IRD)
This is how IRD works. Let's say you got a 5 year fixed, but sell in year 2. You are breaking your mortgage 3 years early; the Bank takes a 3 year fixed rate , calculates the difference in interest between the 3 year fixed rate and your rate, and that is your penalty (if is higher than 3 months interest).
The Banks tend to fuck people hard on IRD, as the rate they use for your mortgage is not the rate you actually pay which you negotiated, but the bullshit posted rate which nobodys pays. IRD penalties can be in 5 figures.