parts missing on Assembly drawings?

[bluebombersfan]

Just got my first Nitro toy ever and have tons of questions. The first one is that I have noticed in the Assembly diagrams/breakdown diagrams not all of the pieces are shown, even in the parts list there are some usually smaller pieces missing that I need. Whats up with that? I've taken apart the rear axle because The differential gears got all broken up some how and I've had a few washers fall that are not even in the diagram so I'm not even a 100% sure where they came from.

 

[slowngreen]

first off, what rig is it? what brand/model?

 

[bluebombersfan]

FS Racing team 2WD ATV 1/10 scale
Here is a link to it
http://www.atv-in-china.com/p/21268/1_10_scale_Nitro_powered_2WD_ATV.html