[john walker's workshop]

a common problem is the toothed ring that is pressed onto the gear to contain the syncro ring looses a lot of teeth and the syncro expands and blocks the shift sleeve. the missing teeth often, but not always, end up in the drainplug magnet, so pull the drainplug and see. if that's the case, other things like the syncro ring, brake bands and stop dogs can get loose and swim around in the gear oil and possibly go thru the gears. that would not be good. best not to drive it in this condition.