If your CD009 swap is making noise, chewing up its input shaft bearing, or destroying pilot bushing adapters, there is a good chance the adapter was never the problem.
The cause is almost always a bearing size mismatch, and it is the single most commonly missed detail in a CD009 conversion.
Watch the explanation
The CD009 comes in three different bearing sizes
Most people do not know this. Depending on the year, a CD009 will have one of three main input shaft bearings:
- 100 mm — the largest, the most common, and the preferred one
- 95 mm
- 90 mm
Every ASE adapter plate is cut for the 100 mm bearing by default, because it is by far the most common. A 100 mm transmission pops straight in with no extra steps.
What happens if you have a 90 or 95
Install the plate against a 90 mm or 95 mm bearing and there is visible play between the bearing and the plate bore. The shaft can move radially inside that gap — and it will, continuously, for as long as the car is driven.
The results follow in order:
- Noise, often the first symptom people notice
- The input shaft bearing itself tears up from the constant radial movement
- The pilot bushing adapter is prematurely damaged and destroyed
That last one is why this matters. For years customers experienced destroyed pilot bushing adapters and concluded the adapters were at fault. They were not. The adapter was being killed by radial movement it was never designed to absorb, caused by a bearing bore mismatch further up the assembly.
The fix: precision laser cut spacer rings
ASE developed precision laser cut spacer rings — reduction rings that convert a smaller bearing up to the 100 mm the plate is cut for.
- The thinner ring converts a 95 mm to 100 mm
- The thicker ring converts a 90 mm to 100 mm
The ring drops over the bearing and locks in. The laser cut tolerance is tight enough that it simply pops into place with no fitting, no shimming and no guesswork. Once it is in, a 95 mm transmission is functionally a 100 mm and the plate seats correctly.
Both rings ship with every current kit
This is now standard on all CD009 kits — both rings are included whether or not you need them today.
Put them somewhere safe even if your transmission is a 100 mm. Here is why that matters, especially for drifters: nothing lasts forever, and when a CD009 fails the cheapest and fastest route is usually to buy another one. The replacement may well have a 90 or 95 mm bearing. If you kept the rings, you already have the solution sitting in a drawer instead of discovering the problem mid-build.
If you bought a kit before this feature existed
The rings are a relatively recent addition, so older CD009 kits did not include them. They are available on their own: CD009 JK Bearing Spacer Rings, 90mm/95mm to 100mm.
Same listing covers replacement sets if yours went missing.
How to check which bearing you have
Measure the outer diameter of the main input shaft bearing on your transmission before you install the plate. If it is 100 mm you are ready to go. If it is 90 or 95, fit the matching ring first.
This takes about thirty seconds and prevents a teardown.
Related parts
The CD009 Pilot Bushing Adapter carries the pilot bearing and is sized to your flywheel center bore — 1.65" or 1.75", so measure before ordering. Running an LS? See the CD009 LSX Pilot Bushing.
Spacer rings are included with all current CD009 conversion kits.