will this hurt the transmission. the only reason why i ask this is cuz one of my dad's friends said don't do this because you ruin it and he had to pay some bucks to fix his and the mechanic said you aren't suppose to do this.
i also showed off my short shifter to this guy i know who also has one and he was shifting without turning the car on and now i m paranoid that something in my trans will break.

 

no...nothing will break. Unless u really *** around with it. Like shift it HARD. Well ive been doing it with empty trans lieing around and they still work great.