[Peck]

with going for design experience, it isn't bad. Personally, i like having a ring (different color and shaped like the actual teeth outermost point) on all gears to represent teeth to make sure i make the spacing correct and provide proper clearance.

Have you set up the mates for gear ratio and tested the output torque/speed of rotation? This is an important part of transmissions in CAD. If you have done this part(or when you do it), have someone (or more then one) who knows how to calculate it by "hand" do so and compare to make sure you did it right. If you are having issues doing this, feel free to ask (keep in mind my only experience designing transmissions is in Solidworks).