Changing Timing Cover with Engine in Car

it is possible, I have done it because of a broken timing chain in a friend's car. I used a stock gasket that I trimmed a bit and also used some black rtv. It's kind-of a ***** getting the seal to seat so the cover lines up. In the end I guess you could just use the RTV by itself, I have heard of guys just using RTV only on their oil pans. Of course you could do it the right way and loosen up all of the pan bolts but what a PITA.