Mark, there isn't much to the reduction drive but it's a BIG job to take it out. The front panel has to come off. The phonelic insulator is very easy to break so be very careful, it's best to remove the screws from the shaft before removing the front panel. Once you have it out it's probably going to take some effort to get it apart. There are small ball bearings in there so be sure to hold it over a container. Here is a good write up explaining how to remove the front panel.
http://freeradiocafe.com/forum/viewtopic.php?f=14&t=4979#p7398 There is a good youtube video, from D-Lab, explaining the process but I can't seem to find it right now but it's there somewhere.
Bob -wb6kwt