nissan micra k11 1.3 gx passanger drive shaft vibration

[kibe]

Hello everyone am antony i need ur help mostly advice .I have a k11 1.3 1995 i had changed the gearbox from ncvt to pressure gearbox that what the mechanic called it but cg13 the new gearbox didnt come with the shafts so we decided to use the old ones but the inner cup connecting to the gearbox had a short gear and the gear box wanted one with long gear so i found them but the shaft had tobe crosss so to fit in the cup so we cut it the joined it and things seemed fine but all of asudden the left driveshaft started giving serious vibrations so i tried to change it but the vibrations still exist between the gearbox and the cup and the mechanic says i have to but a new gear box isnt ther anything i can do ? pleeease advice