I have a VW Golf MK2(2nd generation golf) 1.3L petrol (Golf CL Manhattan is it's full name) with a manual transmission that gets stuck especially in the lower gears. I first diagnosed the problem few months ago when I was at a toll booth at the highway. I was driving for about 2 hours(5fth gear) when I stopped to pay the tolls. I put the car in first gear and when I went to change into second the lever got stuck. I couldn't pull into neutral. From that moment it keeps happening after I drive the car for a long time(not when the car is cold) and seems to happen on all gears both when trying to upshift or downshift. When I manage to pull into neutral then it goes into gear no problem. The only way I've found to combat the problem is to rev really high before upshiftng or pressing the clutch and bliping the throttle very hard. Again, I do that just to unstuck the lever and put it to neutral. After that it goes into gear fine whithout the need to revmatch or anything. 

I went to two mechanics and neither of them seem to have an answer. The clutch is not new but it works fairly fine(revs drops when pressed, car stalls when I let out the clutch with the handbrake on). I also sprayed the clutch cable with WD40 and cleaned the lever area. Transmission fluid is on the right level. 

My first thought was (and still is) that the transmission is falling apart but I've driven 20 to 25 thousand Km(15.000 miles) since then and it still hasn't failed catastrophically. What are your thoughts? Syncros? Clutch? Fluid? Or something stupid like a five dollar plastic piece of the gear lever?