C8 transmission problem
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2nd Gear
Joined: Dec 2022
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C8 transmission problem
I have a 22 HTC w/2K miles. Transmission only operates on m mode, w paddle shift. I only have 2, 4, 6 and 8 gears..anyone else? Currently at dealership with 8 -12 weeks before a tech can look at it..I’m told it has 4 codes. Check engine light is on. Never tracked it or driven like an idiot. HELP?
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No kidding around, are you in another country? There are waits like that for a tech but haven't heard of that long in the US, unless the service dept. has said something else like having to take out the trans. Or, you didn't buy it from this dealer so they're putting you at the back of the line for more service.
Drifting
Joined: Apr 2022
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From: Melbourne Florida’s Barrier Islands
Have you ever had the filter or fluid changed in the transmission changed?
I know it’s only 2000 miles for you, but I’m wondering how paranoid I should be when I get mine. I’m thinking 500 mile fluid change and 1500 mile filter and fluid plus two quarts.
I know it’s only 2000 miles for you, but I’m wondering how paranoid I should be when I get mine. I’m thinking 500 mile fluid change and 1500 mile filter and fluid plus two quarts.
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8-12 weeks to get a tech to look at your car is nuts. Call other dealers and see what their wait list is - surely you can find one that can look at the car in a more timely fashion.
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No kidding around, are you in another country? There are waits like that for a tech but haven't heard of that long in the US, unless the service dept. has said something else like having to take out the trans. Or, you didn't buy it from this dealer so they're putting you at the back of the line for more service.
I would find another service center.
^^
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I have a 22 HTC w/2K miles. Transmission only operates on m mode, w paddle shift. I only have 2, 4, 6 and 8 gears..anyone else? Currently at dealership with 8 -12 weeks before a tech can look at it..I’m told it has 4 codes. Check engine light is on. Never tracked it or driven like an idiot. HELP?
Procedures aka Hydraulic Control System Cleaning Procedure listed in the 2020 Service Manual. In later versions there is a procedure called a Hydralulic System Flush - I suspect this is the same as one, or more, of the former procedures. In any case, it is a computer controlled manipulation of the solenoid valves with a goal of freeing debris that may be trapped there, causing the problem, and moving it to the filter, which forum members have reported as being changed after the procedure. Many have reported this as successfully solving the problem. One member has reported that the Hydraulic System Flush takes just 20 minutes. If it fails, then there will likely be wait for a part, or parts anyway. The point is, a dealer could take a look and either fix it quickly, or find the problem and schedule the necessary repair.
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2nd Gear
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Drifting
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From: Melbourne Florida’s Barrier Islands
it seems like failures either happen early in the DCTs life or never. Isn’t that why GM has an investigation going on for this tranny. Or do you think the investigation was started to avoid a recall?
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I suspect the investigation was to determine if the failures were caused by contamination and, if contamination, whether the contamination was left over from the manufacturing process or self generated contamination during operation; and if there was sufficient contamination being captured to overwhelm the filter in less than 7500 miles to cause it to bypass.
Drifting
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From: Melbourne Florida’s Barrier Islands
I suspect the investigation was to determine if the failures were caused by contamination and, if contamination, whether the contamination was left over from the manufacturing process or self generated contamination during operation; and if there was sufficient contamination being captured to overwhelm the filter in less than 7500 miles to cause it to bypass.
I suspect the design is very good on paper, but very sensitive to contamination as you pointed out. Executing a build on something like this tranny in less than clean room conditions seems to elude GM, that’s why I am going to follow the protocol I posted earlier.
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Recalls are usually safety related, it is debatable whether or not the tranny issues are a safety concern, but the investigation began over a year ago, with failures occurring about 4 years ago.
I suspect the design is very good on paper, but very sensitive to contamination as you pointed out. Executing a build on something like this tranny in less than clean room conditions seems to elude GM, that’s why I am going to follow the protocol I posted earlier.
I suspect the design is very good on paper, but very sensitive to contamination as you pointed out. Executing a build on something like this tranny in less than clean room conditions seems to elude GM, that’s why I am going to follow the protocol I posted earlier.