Truck having issues going into third gear

[Redland1]

Having issues putting the shifter into third gear lately. It’s a 13 speed Eaton Fuller. The day before it started the shifter was twisting when I would try to shift and I found a spot to pull over to check it out. Pulled up on the shifter and it came off the transmission. Ended up opening up the boot and saw that the bolt had come off and was sitting on top of the transmission so I put it back on with a lock nut.