I understand what you are saying. I have ran mine and shut off the engine while in gear many times & coasted into my garage while still in Drive, no issues. It may be the bolt on the output shaft of the Zf has loosened-up. The bolt is accessible by removing the cover off the rear of the LT230 (where you would hookup a PTO or overdrive) but I'm pretty sure the gear-set (part of the transfer case) that's in there has to be removed too to see it & get a socket on it to check the bolt's tightness. The gear-set should slide or screw right out into your hand.