Not sure if this was your issue, but when you get a new/used one remove the tack welds on the locking pin and weld that pin all the way around on both sides. Just a little bit of added insurance that a member from a different site gave me. Added a picture of the piece I'm talking about. I don't think I remembered to take a picture of it after I had it completely welded.
-2011 Polaris RZR-4 800 (SOLD)
-1999 Polaris Sportsman 500 ATV
-2006 AC Prowler 650XT (SOLD)-- updated bevel gears, updated oil pump driven gear, 4 wheel disc brakes, line lock E-brake, Papa Slap clutch, Xentec HID's, Dynatek CDI, Warn skid plates, Intellitronix gauges, 2010 intake/cvt duct work and dust shield, RZR seats, Bestop folding windshield, full cab kit, rear cage and rear seats (4 seater)