Lets say you are about to remove the center shaft cup so to take out a bad spur gear. What if the hex screw is so tight it just cannot be removed? It is bad luck but it does happen….
You can do this from the rear gear box. First you open up the gear box and take out the diff unit, exposing the cup shaft. Then you slowly take out the remaining spider gear. There may be a small e-clip to hold the shaft and the spider gear together – you will have to take it out if there is one.
Now it is completely out of the gearbox, and you will need to use a little bit of force to cut away the bad spur gear. As you can see from the photo, there is a king pin in there so you will have no choice but to cut away the spur gear. It is plastic anyway.
Because of the need for this king pin, you cannot simply plug in a new spur gear. You need to cut open one side of the pin holder so you can squeeze the king pin back in.
If this spur gear is of a different size than the previous one, you will also need to change the pinion gear so to achieve the desired gear ratio.
To make sure the king pin won’t fall out, apply a drop of super glue.
