Your gearbox is stripped... happened twice to us on a 2015 3800. Go to Dyers Rv online and order a new gearbox, I posted a long explanation here a couple of weeks back with pics of the gearbox. The motor and gearbox is on top of the slide in the middle. You can have someone push/pull the slide while holding the button and it should work till you get it fixed...
2009 F350 SRW 6.4 Diesel w/Spartan tuner, AFE exhaust, AFE cold air intake, Airlift 5000 ultimate bags with wireless air compressor.
2015 Voltage 3800 Epic 4 package