Problem is one of the cables come loose from the shifter. It is stuck in 5th gear. The shifter moves front to back freely.
I do not have it taken apart from the bottom side yet but from top side I can see the cable is not connected to the shifter. It has a round hole on the end. From previous experience with other cars I would assume the bushing wore out and needs replaced.
In the link you provided in the third/last diagram it appears I need part #24.