First check the play in the gears. The gears should remain tight when jostled. To see a bad shim washer click here. More information about shim washers can be found below Using the circlip tool, remove the circlip around the rear axle. This will allow for the shim washer and the gears to be removed.

Remove the shim washers and the gears. Marking the gears with a grease pencil will identify which side faces up when reassembling.

You can now remove the selector rod, the rod washer and the cruciform. This shaft uses a left hand thread, meaning everything is backwards. To loosen turn clockwise, to tighten turn counter-clockwise.

Sinch the lighting was pretty bad, we took the rear axle out of the engine to give you a better view of this part. You don't have to do this. For all this work, you can now treat yourself to a pickle. We certainly did :))

Here's the selector rod. It's a chunk of metal with a small washer on the end. The threaded piece threads into the cruciform.

Turn the cruciform by hand until it is parallel with the rear axle slot. You can now just push the cruciform out through the side of the slot. place the new cruciform into the slot. The Cruciform will be fitted with the bend in the legs facing the rear wheel.

This picture illustrates the damage caused to the cruciform by shifting between the gears. Always use Piaggio cruciforms when replacing the old one. The cheaper parts tend to wear faster and do not have as pronounced of a bend making them hard to fit correctly.