Thanks everyone for inviting me, first post. I have a 2009 gxl 200 with the dreaded 4lo light flashing, I have pulled both centre diff lock and 4 lo actuators apart many times but this time has got me stumped, I have cleaned the hot spots in housing, tested micro switch and reinstalled and fixed the issue, then I did the CDL put back together and fixed it as well, I then retested the 4lo and light was back to flashing. I have looked at several you tubes following their positioning of gears and shaft in transfer case which I believe I have done right. I have pulled it apart a dozen times and can not find a problem. With engine off and in neutral you can here actuator working, but sounds like it's locking then unlocking with light flashing on dash, turn engine on and it sounds like it's grinding with a terrible sound trying to engage, disconnected battery to reset computer that didn't work, lifted back wheel up to see if there was wind up which didn't work either, Sorry for the long post but best way to discribe it. With actuator in my hand (see video) it appears to work and light comes on solid, i then reinstall the housing and it's not engaging again. Any ideas I would be grateful.