Nissan CD009 6-Speed
Problems and Cost

Early 350Z and G35 6-speeds used the FS6R31A. The CD009 arrived with the 2007 VQ35HR cars and carried on through the 370Z, the manual G37, and some later manual G35s. It is a stout box for the power these cars make, and it holds up well to boost in mild-to-moderate builds, which is why junkyard and used CD009s became a popular swap transmission and why used prices went up.

The weak spots are not the gears or the case. They are the synchros, mainly 3rd, and on the 370Z and G37 the clutch hydraulics that sit around the box.

Common CD009 Problems

3rd gear grind

This is the classic CD009 complaint. The 2-3 shift grinds or crunches, usually at higher RPM and usually when the shift is quick. It often starts only when the fluid is hot or only on hard driving, then spreads to everyday shifts. The 3rd gear synchro is the common cause. Once the ring is worn, there is no fluid or adjustment that fixes it; it needs a teardown. Our synchro wear guide covers how to confirm it.

2nd gear grind

Second-gear grind is the next most common, and it shows up most in cars that see track days or hard 1-2 shifts. A 2nd gear grind that only happens cold and goes away when warm is often the fluid. One that happens hot and at speed is usually synchro wear.

Synchro wear from hard launches and power shifts

Launch control, drag launches, and full-throttle shifts are where CD009 synchros go to die. Power shifting asks the synchro to stop a spinning gear while the clutch is not fully released. Do it often enough and the rings glaze or wear. On modified cars with a heavier clutch, a sticky or slow-releasing clutch makes it worse, because the box is being asked to sync against drag it was not built for.

Rev hang and the "rev-up" confusion

These drive-by-wire VQ engines hold RPM for a moment between shifts. Drivers fighting that hang tend to force the shifter, which wears synchros faster. The 370Z SynchroRev Match feature blips the throttle on downshifts and helps the synchros when it is on. Separately, the 2005-2006 "Rev Up" 350Z engine is known for oil consumption. That is an engine issue, not a transmission one.

370Z and G37 Clutch Hydraulics: CSC and the Delay Valve

The 350Z and G35 use an external slave cylinder on the side of the bellhousing. The 370Z and G37 moved to a concentric slave cylinder (CSC) that sits inside the bellhousing around the input shaft. The upside is a clean design. The downside is that a leaking or failing CSC means pulling the transmission. Our concentric vs external slave cylinder guide explains the trade-off.

• Pedal sticking to the floor or going soft after hard driving. A known 370Z complaint, tied to heat soak in the clutch hydraulics. Fluid that has absorbed moisture boils sooner, so flush it. Nissan revised parts over the years; have the dealer check for updates on your VIN.
• Leaking CSC. Fluid on the bottom of the bellhousing, a pedal that slowly drops, or trouble getting into gear at a stop. When it gets that far, the clutch disc is usually soaked too.
• The clutch delay valve. Nissan put a restrictor in the hydraulic line that slows clutch engagement to protect the drivetrain from sloppy launches. It also makes the clutch feel vague and makes quick shifts harder, and owners commonly remove it or install a line without it. It is a cheap fix that makes the car nicer to drive.

Rule of thumb: if the transmission is coming out for a CSC, replace the clutch, pilot bearing and CSC together. If the transmission is coming out for a synchro rebuild on a car with more than a few years on the CSC, replace it then too. You do not want to pay for the same labor twice.

Noise Diagnosis

• Grind only on a specific shift: synchro wear on that gear, or a clutch that is not fully releasing. If every gear grinds, suspect the clutch hydraulics first.
• Rattle at idle in neutral that stops with the pedal down: often the stock dual mass flywheel. See the dual mass flywheel guide.
• Chirp or squeal only with the pedal down: release bearing or pilot bearing.
• Whine that changes with road speed in every gear: check the differential and wheel bearings before blaming the box.

Rebuild, Used Unit, or Flywheel Swap?

If the only problem is a 3rd gear grind, a synchro rebuild is the right fix. A shop that knows these boxes can replace the rings, sleeves and bearings that need it. A used CD009 with unknown history can carry the same worn synchro you are trying to get rid of, and swap demand has pushed used prices up to where the gap with a rebuild is smaller than it used to be.

While the box is out, decide on the flywheel. Many owners replace the stock dual mass unit with a single mass flywheel like the ACT XACT Streetlite, which fits 2007-2009 350Z, 2009-2016 370Z and 2008-2013 G37. Expect more gear rattle and quicker revs; read our lightweight vs stock flywheel guide before you decide. Pull the old pilot bearing with a pilot bearing puller, use a clutch alignment kit to center the new disc, and check the clutch kit buyer's guide.

Fluid

Use the GL-4 manual transmission fluid called out in your owner's manual. A quality GL-4 75W-90 like Red Line MT-90 is a common choice and works well with the brass synchros. Change it after any synchro work and every few track days. Fresh fluid will not fix a worn synchro, but old, sheared fluid makes a marginal one grind sooner. More in our gear oil guide.

What It Costs

Ballpark numbers. Synchro parts are often dealer-only, so lead time can be the real cost. Budget for a clutch and pilot bearing any time the box comes out. For hard parts beyond what we stock, our sister store CoreTransmissionParts.com carries more transmission parts.

FAQ

Why does my CD009 grind going into 3rd gear?

The most common cause is a worn 3rd gear synchro, which shows up first on fast, high-RPM 2-3 shifts and when the fluid is hot. Rule out the clutch hydraulics first, since a slave cylinder or clutch that is not fully releasing can cause the same grind. If the hydraulics are good, the fix is a synchro rebuild.

Which cars have the CD009 transmission?

The CD009 is the 6-speed manual in the 2007 and later 350Z, the 370Z, the manual G37, and some later manual G35s. Earlier 350Z and G35 6-speeds used the FS6R31A. The CD009 is also a popular swap transmission because of its strength.

What is the 370Z clutch delay valve?

It is a restrictor in the clutch hydraulic line that slows how fast the clutch engages, meant to protect the drivetrain from harsh launches. It also makes the clutch feel vague and quick shifts harder, so many owners remove it or install a line without it.

Should I rebuild my CD009 or buy a used one?

If the only issue is synchro wear, a rebuild by a shop that knows the box is usually the better choice. A used CD009 with unknown history may have the same worn synchros, and swap demand has pushed used prices up. Replace the clutch and pilot bearing either way.

What fluid does the CD009 use?

Use the GL-4 manual transmission fluid specified in your owner's manual. A quality GL-4 75W-90 such as Red Line MT-90 is a common choice that works well with brass synchros. Change it after any synchro work and more often on cars that see track use.