How about this; Start taking it apart and get a feel for all the parts and report back when you hit a snag. Check the pinion height before you take it out. Take plenty of pictures.
I am good at taking things apart. I'm really good at that part. When I was six, I talked my brother into disassembling his toy top to see what made it whistle. When I was finished, all the metal tabs that held it together had broken off and we had still not found the magic whistle inside. (you probably guessed by now it was the holes punched in the side) If I had been nine, we would have soldered it back together. My mom solved that problem, much to my distress, by transferring tags, title and ownership for my toy top to my brother.
Through life I've gotten very good at taking things apart. That helps understand how things work and that is usually worthwhile if you can put them back together. Later in life I learned how to put some things back together afterwards. I sort of learned to ask about this last step first, before it's too late.
