I think I read somewhere here recently about a similar problem. I was driving to work a week before Christmas when I missed a gear. Then I couldn't get any gears for a while. After I slowed down, the gears came back, except now it crunches into 5th gear, more especially when the car is warm. I've taken the end-plate off the gearbox (which you can do beneath the driver's side wheel arch) and exposed the 5th gear. The synchro ring just dropped off the end of the shaft, but there doesn't appear to be anything to hold it there anyway! There doesn't appear to be any damage, but I desperately need a picture of what it's supposed to look like. Also, what type of oil goes in the box, as I can't read japanese. Any help welcome.