check? and if its low or doesnt have any, just drain whats left and take off the clutch cover and check the shifting mechanisim. do you have any engine/transmision knowledge? if not, we can help out. just ask. pictures of the shift shaft, shift star and spring wheel and theres a kinda C shaped claw with a spring on the end of the shift shaft that crabs the star gear and spins it. that could be your problem, if either the spring on its gone, or the C tips are worn or broken.
by the way, when you take off the clutch cover(AFTER draining tranny oil) still have a pan under the engine(obviously under that spot) and some rags handy because oil still spills out even after draining it. like not just a bit, quite alot comes out. i learned from experience lol...
PICS OF EVERYTHING! just take a bunch after you get it open.