89 sr5 wont go into gear.

ok, so one day i drive to work come out hours later start the truck and it wont go into gear. Its stuck in neutral, no grinding or other sounds just wount go into any gear. 4wd is on 2wh and fully engaged but still nothing...any ideas?

Could one of three things, clutch, tranny, or the shifter.
The shifter has a rubber seat that deteriorates and can cause shifting problems, so that may be a good place to start.