Project Miata – Shifter Rebuild

2023-12-11 · via Frank's Weblog

中文版：Project Miata – 换挡杆维护 – Frank’s Weblog

Recently I found the shifter is very stiff on my Miata, and shifter has a lot of play no matter in neutral or in gear. I realized the shifter needs some care.

I bought a shifter rebuild kit from Treasure Coast Miata: New OEM ’90 – ’05 5 speed Shifter Full Maintenance Kit

Besides the items in the kit, you’ll need:

75W-90 Gear oil*
A turkey baster of syringe to extract old oil from turret
Shifter boot leather(not included in the kit)

Scarlett: Both the manual transmission and the differential takes 75W-90 gear oil. However, the differential requires GL5 while transmission requires GL4. You can use either GL4 or GL5 in the turret.

I didn’t expect the existing parts to be in a good condition, but I was still surprised when I revealed the shifter parts. A good amount of rubber on the upper shifter boot has completely gone. Most likely the shifter was never serviced before.

Look how much play is there!

When I pull out the shifter stick I immediately noticed something is wrong — where is the bushing?

Remove the old oil with syringe or turkey baster.

The OEM plastic bushing is already broken into pieces. I managed to fish them out.

Remove the old parts from the shifter stick, re-assemble the shifter stick with new parts, following this diagram. On my shifter the half moon bushing was broken and one of the pieces were stuck in the shifter. I ended up drilling it out.

There are one bushing and one washer in the turret, replace them with new parts, fill the turret with oil. It takes 3oz(around 90ml) I used Valvoline 75W-90 GL5 gear oil(same as differential). Put the shifter stick back in.

Shifting is much more better.