On my Mule one of the vacuum hoses was pinched off it stuck in same mode yours did.
Sorry warranty work don't know if was one comming in to selector switch or going out(toward actuator) believe one coming in. It was inside the cab behind/under the dash.
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Bill Thomas
Missouri Mule - 96 Wht 4X4 ST CC,5 spd, 3. 54, 8 ft bed, 1 ft high cheater boards.
99 Freightliner bl/wht FL60 ISB-5. 9 24v,215 hp,520 tq,6 spd, 3. 59 nsr,16 ft box, 19. 5 tires,Wt/gvw 11,000/23000