Tractor Repair: 3588 2+2 transmission, forward gears, shift fork

Question
Transmission will go into reverse but as you try to move the shifter to the high or low forward gears there is no resistance to the shifter.  Needless to say it does not go into these gears and the tractor does not move.  After watching the shifter linkage on the outside or the transmission ( every thing appears to be moving)  I am assuming that the shifting forks or internal linkage came loose.  Question.  is this something that the tractor would have to be split apart for, Or is there another way to get to the linkage?  Any ideas to the issue would be great.

Answer
  The first thing to do is remove the seat and floor plates so you can get at the range transmission cover.  Remove the shift console and linkages and then remove the transmission cover.  You will probably find a broken shift fork or rail.  Whether or not the tractor needs to be split depends on what you actually find wrong once the cover is removed.