This model is inspired by this adapter: https://cults3d.com/en/3d-model/game/adaptador-secuencial-logitech-g29-g27-sequential-adapter-logitech-g29-g27. The model is good but I wanted it to be more tight fitting and to be able to use harder elastic bands, so I remade the model from scratch.
You will also need one or multiple elastic bands that you can put between the two pillars to help the shifter return to the centre.
The adapter is placed under the dust cover of the shifter.
The author hasn't provided the model origin yet.