I am currently working on a 2002 yamaha big bear 400 with 4x4. I was driving it after running through the trails with my buddies and i was running on gravel road to get back to the house. While riding back the 4x4 started throwing itself in an out of 4x4. It's not an electrical issue. If I drive it it will pop in and out by itself and I need to know what might be the issue.

I have the front differential out of the atv right now and I am started to tear it apart.What might be the issue?
also does anybody know where I can get a pdf for my atv or a diagram for dissasembly of the front diff.
Thanks!

 

Do a search for yamaha parts and most any site you find will have diagrams after you've entered the year and model. You can vaguely see how they fit together. That might not be a great help, but its a quick way to see what you're dealing with.