Unless something is broken, nothing will fly out when you take that cover off. All the gears, springs, everything, all come out together. Some of the shims for the gears might come out, but all the shafts are different sizes, so you can tell what fits what.
Now your problem...
1) Try adjusting the rear brake a little bit. I had a similar problem with a '79 express, and that's all it was.
2) If that doesn't work, take the cover off, and make sure the ratchet pawl and spring are not broken. The ratchet spring can be tricky to install correctly.
3) Make sure the starter spring itself is installed correctly. It could be binding up.