One would be hi and low range and the other would be 4 wheel drive on or off, not sure about the 3rd stick. Does this vehicle have a pto powered winch or something similar?
Read this article on twin-stick transfer case conversions ----- https://www.novak- adapt.com/catalog/shifters/dana-20-twin-stix
Twin stick allows you to transfer power to one axle or both at the same time.
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