and taking the whole assembly out of the car is the easiest. For the Z - it involves removing the interior hatch trim panels (and on my 2+2 that can be a bit of a pain)....
Once you get the assembly on your workbench - remove the screws holding the "pusher" reel cap and it will be obvious what to do next. After cleaning up the broken pieces of plastic inside -- I lub'd everything up with some white lithium grease. Also best to plug the assembly into the harness before installing into the car and verify it goes up and down properly. Sometimes they have to be operated a few times (up/down) before all is OK...
