200tdi gearbox cant get 3rd and 4th

hi my 86 tdi 110 has been running great but last week just got a mile from house and couldnt get 3rd and 4th gear and very hard to push into 1st and 2nd, its the same if engine running or not so not clutch issue! oil level is good\! have took the top of box off and nothing looks out of place [for all i know!] any body any ideas on what the problem could be? was supposed to have been a recon box 12 month ago and gears have always been easy to find and smooth! thanks in advance!

is stick loose or stiff

stiff when on gearbox nice and loose when took off

vandrover said:

stiff when on gearbox nice and loose when took off

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obviously off it will be,side to side when on or just forward/ back or both

forward/back

Is it all gears inc rev. Slave cylinder push rod might be on its way through the fork?

remove the top see if its stiff or box selector if its box it will need to come apart

its box then! rod very hard forward and back! are they hard to fix or shall i just get another box?

It's not rocket science........ More o level chemistry. There's loads of online tutorials and get the workshop book, it is an lt77 is it?