Anyone have any suggestions to 2 problems dealer cant solve?

1. gets hot & shuts down till totally cooled down. Valves have been re-adjusted & it runs better but now vibrates like hell instead of quitting!
2. Sporadically can only get Nuetral & Reverse. it's Hell backing out of a forest! oOccasionally I get it out of 1st gear and then I cant get it out of 1st gear. Aafter a while, with no "Rhyme or Reason", it will start acting normally and when I get it to the dealer, they cant duplicate the problem & thusly cant fix the problem.

Has anyone ran into this B4 or have any idea where this "ghost" is??
i get 1st gear & then can't get it out of 1st! both of these things happen often but usually quit. Every time I take it to the dealer, they can't duplicate the problem & therefore cant fix it