I purchased a wooden gear knob to replace the one on my 1994 4/4 ford zetek 1800 which looks to modern and plastic looking with the 5 gear numbers on top, the wooden one i purchased has a threded metal inner and looks as if it will be perfect. But i cant get the old one off ,there does not appear to be any grub screws i have asked at Melvin Rutter where i purchased it and i have asked at the local ford garage who suggested i molegrip the shaft and twist the knob hard which i tried, it moved a fraction but now its a bit loose but wont turn or twist off i have also removed the plastic cap from the top of the knob hoping to find a screw,but no luck .Can anybody advise.