MX-5 / RX-8 Manual Transmission Change Control Bush Replacement
It's well known that the manual 6-speed transmission in the NC and RX8 is a weak link.
While this bush doesn't fix those inherent design flaws, it can help make those shifts a little more precise (due to higher tolerance bush) and replaces the OEM plastic bush that can break under heavy use.
Tools needed:
10mm socket/spanner
12mm socket/spanner
Circlip players with 90° fingers
5-6mm drift
3mm drift
Remove the change control system
Remove the 12mm bolts and gently pry the Change Control system from the gearbox housing and flip upside down.
Remove the change control system
Remove the 12mm bolts and gently pry the Change Control system from the gearbox housing and flip upside down.
Remove the change control system from the top plate
Remove all of the 10mm bolts that hold the change control system to the top plate, making note of the oil shoot placement, and put the top plate to one side.
Use a 6mm drift to flush the top of the pin before driving through with a 3mm.
Replace the plastic bush with brass one supplied - a drop of oil helps. Reassemble the rod end and drift the pin back through
Drift the pin through the selector fork and remove the rod to gain access to the 2nd bush.
Install the bush and reassemble - a drop of oil makes this easier. Then reassemble and drift through the pin.
Once reassembled, you can reassemble the fork carrier to the top plate with the 10mm bolts. This concludes the assembly of these 2 bushes.
Remove the 10mm bolt from the adjuster plate (no need to touch the adjuster)
Use circlip pliers to remove the circlip (90° fingers help as space is tight), and remove the pin from the gearbox housing, allowing removal of the selector arm.
Remove the c-clip and replace the bush before reinstalling the c-clip. The selector can now be reinstalled in the gearbox with the previously removed adjustment pin. Bolt down the pin plate and add the circlip. You can now reinstall the top plate assembly with the 12mm bolts.
Job done.