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Some 2023 Corvette Z06 Units Were Serviced With The Wrong Main Control Valve Body

Some units of the 2023 Corvette Z06 were serviced with the wrong main control valve body, affecting the mid-engine sports car’s eight-speed dual-clutch transmission. To address the issue, GM has released a new Customer Satisfaction Program.

The Customer Satisfaction Program is tagged with reference number N232418320 and was released in January of 2024. The program only affects units of the Corvette Z06 produced for the 2023 model year. GM did not specify the number of units potentially affected by this issue.

Some units of the 2023 Corvette Z06 were serviced with the wrong main control valve body.

The main control valve body is a major component of the transmission, with this new Customer Satisfaction Program affecting the C8 Z06’s dual-clutch eight-speed automatic transmission (RPO code M1M) co-developed with Tremec. To address this issue, dealers are instructed to replace the incorrect main control valve body with the correct unit. It’s estimated that the procedure will take 4.6 hours of labor time to complete.

The M1M dual-clutch eight-speed automatic transmission is exclusive to the 2023 Corvette Z06. Although the transmission is similar to the M1L unit equipping the C8 Corvette Stingray, the M1M in the C8 Corvette Z06 includes a shorter 5.56 final drive ratio. The C8 Corvette Z06 also incorporates specific wheels, tires, and suspension.

Just behind the cabin, the 2023 Corvette Z06 cradles the naturally aspirated 5.5L V8 LT6 gasoline engine, which is rated at 670 horsepower at 8,400 rpm and 460 pound-feet of torque at 6,300 rpm. The LT6 features a lightweight rotating assembly and flat-plane crankshaft, and can spin up to a maximum engine speed of 8,600 rpm. The LT6 also features twin 87 mm throttle bodies and a dry-sump oiling system.

Under the body, the C8 Corvette Z06 rides on the Y2 platform, the same architecture that underpins the C8 Corvette Stingray. Production takes place at the GM Bowling Green plant in Kentucky.

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Jonathan is an automotive journalist based out of Southern California. He loves anything and everything on four wheels.

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Comments

  1. I have a new 2023 Z06 and was wondering if anyone knows exactly what “serviced” means in “some units of the 2023 Corvette Z06 were serviced with the wrong main control valve body” in this article. Does it mean they came from the factory that way or when taken to a dealer for service they came out that way?

    Reply
  2. Wrong part(s) installed at the factory.

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    1. Thanks!!

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      1. If I understand this correctly the factory ( Corvette) didn’t screw up. I think the trans are a joint venture between GM and Tremec in Wixom MI. The Vette factory just installs them in the car.
        I’m guessing some got the wrong valve bodies although I’m confused by the service part of it. Maybe at the 7,500 mi service they change the valve body but I wouldn’t know why.
        At the 1,000 mi check up the changed my trans filter and oil. For sure didn’t work on the car for 4.5 hrs. Hoping they come out with some VIN #s or build dates so we know what cars are affected.
        This is just a guess on my part. Doesn’t mean I know what I’m talking about. Thank u

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    2. It means there’s absolutely no quality control no matter what the hell you spend for a car this s***’s ridiculous they’ve been building cars for a hundred plus years and they can’t build a car with the right parts on it and nobody catches it on down the line. BS

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      1. Other well-known/respected company(s) currently have problems installing parts correctly on their aircraft. There seem to be issues that are crossing industry lines. In the case of Boeing, the company lost a lot of experienced people during and shortly after the covid epidemic. This problem is magnified by extreme pressure to get planes out the door. I wonder if GM isn’t experiencing something similar.

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  3. Dates of build and VIN #s please. Thank u

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  4. 8/9/2023, 1G1YF2D37P5604362. John

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  5. Are they making any erays yet? Does anyone know?Jerry

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  6. I thought they started making them a few weeks ago. Could be wrong

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    1. What gear set. Who said anything about a gear set.

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      1. I misread the information regarding the gear set. It appears to only be the valve body that’s an issue.

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  7. So how do I know if GM screwed up my 160000 dollar car?

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    1. GM should contact you. Otherwise, I’d check with my selling dealer to see if they have any additional information. Given the difference in the differential ratio you should be able to check which gearset you have, assuming that the gear sets in the transmission are the same. There should be an easily measurable difference between top gear RPM at say 100 mph between the bad gear set and the correct gear set.

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  8. Guys, relax. The transmission was assembled @ Tremec. It looks as it may come down to a standard Stingray valve body got into the Z06 unit. May be as simple as the box with 10-12 valve body’s was mislabeled. YES, somebody screwed up. As far as quality control the valve body would be considered an internal part. Once the oil pan is installed on transmission nobody can visually see it.
    The transmissions are shipped to Bowling Green, they are installed in the car. One should assume this is related to a very low number of vehicles?
    Again, don’t knock GM or Chevrolet for this, it’s kind of out of their control at assembly line. It’s not the end of the world,
    – hit happens. If UR involved you’ll be notified, take your baby in and your dealer will give U a loaner and it will all be over in less than a day. Trust me it’s MUCH worse with Ferrari, Lambo, the higher the price typically the worse it can be. Don’t ask about experiences with those.

    Reply
  9. Wonder if this has anything to do with the ones that were shipped from the plant to MI. we keep hearing about.

    Reply

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