Mule 3010 when 4wd is engaged there is a loud clicking in the front driveline or axle, when you disengage the 4wd it seems to persist for a while like it cound be staying in 4wd. Operates and functions as normal but the noise.

 

hmm, kinda sounds like the gears are wearing on the ends and are not fully meshing (and or worn by now). I have no experience with your ride. But it was a thought.