I have a 2006 polaris ranger XP, it's amazing and runs fine at 189 hours. But my problem is about two or three weeks ago i was drive through some mud with the 2wd switch on to do some roster tails in the mud but the 4wd engaged. And it's been like that from now on. I beleive the front diff disengages, but i was wondering why the 4wd engeages even if the 1wd or 2wd switch is on?

If any advice please help me

 

The front "diff" is not a true differential...it is a bi-directional one-way roller clutch. There are a bunch of cylindrical rollers that are held into a cage assembly with a spring that wraps around the assembly. When AWD is selected an electromagnet is energized, putting drag on the roller's cage. When relative motion exists between the cage and the outer housing, the rollers cam out and wedge, transfering torque. It is possible that the rollers jammed due to a high shock load (did you hit AWD while the rear wheels were spinning out?). Usually, driving in reverse a bit will unlock them. Another possibility is that the spring that normally holds the rollers has weakened and centrifugal force of the rollers is initiating the wedging effect that locks the unit. Another possibility is that the cage that holds the rollers has cracked, allowing things to misalign and jam.