I have a 2003 hyundai tiburon, And randomly my shifter wont shift into 5th, 6th, or reverse.

All my other gears work just fine. 1st is 1st, 2nd is 2nd, but then 3rd is first gear again, 4th is 2nd gear, 5th is 3rd gear, and 6th is 4th gear. and there is no reverse. Would this be in the linkage or the transmission do you think?