a small bolt holds the plastic cable end down to the tranny case and there is a "O" ring gasket on that end that seals the cable to the hole in the case. Once you undo the bolt and pull up on the cable housing there is a steel wire that you'll see that is hooked to the cable inside the housing. Need to unhook the wire in order to replace the O ring. If the plastic housing is not broken you can even just put gasket maker silicone around the end base and bolt it back down which may stop the leak too. Depending how full the tranny is, oil may pour out the hole when you undo the cable. Not complicated at all.
