the hub is easy to take apart slip the wheel hub off mostlikle it will just need to be cleaned up.
once you get down to the round plate with the 3 little tabs turn on the 4x4 and see if the plate magnetises against the hub if it dose just clean the parts and put it back together.
\you will not be able to move the plate with your fingers if its working if you can somthings wrong with the hub...
Im not much of a typer so call me if this dosnt make since.
I rebuild ONLY Polaris motors and atv's as a hobby Todd 972 896 1002