Unknown demon issue lo flashing n buzzer no gear at start

Hello all I have demon on my 2007 tundra 5.7 dbl cab trd , problem having is on short drives when get in to leave again ( 5 to 20 minute drive )I get beeping buzzer and the 4*4 lo light blinking and try putting in gear and acts like it's in park or nurtrual in any gear but when this happens and put back in park I get like grinding noise ( for example) like driving a manual trying to find gear . Some times I just have to shut ignition off pull key out wait a minute or two restart and like nothing happen but when this don't work and I just idle I can put in neutral and few seconds I here few clicks buzzer and the low light shut off and on my way so checked all fluids 1st and for any leaks all dry and levals perfect ( why Toyota engineered fluid check and fill areas in the tightest areas is beyond me) so took to Toyota dealer and no surprise they said can't find anything wrong everything seems to be at specs but trued to get me in new truck cuz said high in milage so here 3 days later after visit to dealer it did it again can anyone steer me in the right direction B4 it turns into a real nightmare cuz today's economy I'd want to buy 1truck for price of two lol yes milage is high 206357 but it is a Toyota thanks in advance and sorry for long post thanks again for your time