Now that we are in the 5th model year for the C8 Corvette, GM has published an updated TechLink article about servicing the Tremec dual-clutch transmission. The TechLink focuses on the DCT’s canister filter and when it should be replaced. GM had previously changed the schedule of when the canister should initially be changed, and then the mileage for follow up changes, so this is a great refresher for Corvette owners who own a C8.
Corvette Transmission Canister Filter and Maintenance Information
The Tremec DCT TR9080 dual clutch transmission (RPO M1L, M1M) (Fig. 1) on 2020-2024 Corvettes features a transmission canister filter that should be replaced at the initial 7,500-mile (12,000-km) maintenance service. After the initial service, the canister filter should be changed at 22,500 miles (36,000 km) and then at regular 22,500-mile (36,000-km) intervals.
The canister filter (Fig. 2) change in the first 7,500 miles (12,000 km) is critical due to the initial break-in of the internal transmission components:
Maintenance Coverage
GM has extended maintenance coverage of the filter (Fig. 3) to two years or 7,500 miles (12,000 km), whichever comes first, on the first filter change to cover vehicles that do not accumulate 7,500 miles in the first year. It is recommended to only replace the filter at the required maintenance intervals due to the loading characteristics of the filter.
The filter does not need to be changed earlier than 7,500 miles (12,000 km). Additional filter changes can be performed, but the recommended mileage intervals should still be followed for regular maintenance. For example, if a customer elects to have the filter changed before 7,500 miles (12,000 km), it should be changed again at 7,500 miles (12,000 km). GM will only cover one filter change.
Check the maintenance schedule in the appropriate Service Information for complete maintenance information. (Fig. 4)
Changing the canister filter at 7,500 miles (12,000 km) has been identified by Engineering as the period when the most contaminants may be created due to the break-in of the transmission components. Engineering recommends that the filter be changed as close to 7,500 miles (12,000 km) as possible – plus/minus 1,000 miles (1,600 km) should not be detrimental.
If a transmission is replaced, it should be treated the same as the new vehicle break-in period. The canister filter maintenance should restart as if it was a new vehicle, with the next filter change at 7,500 miles (12,000 km) after transmission replacement.
TIP: Filter change information should be shared with your service advisors and service management. GM will be reviewing maintenance records on transmission warranty claims. Lack of maintenance on the canister filter cartridge may affect warranty coverage.
Maintenance Minder
Beginning with the 2023 model year, the Corvette has a maintenance minder on the Driver Information Center that will display a maintenance message shortly before the 7,500-mile (12,000-km) maintenance interval. (Fig. 5) The message also will appear every 22,500 miles (36,000 km). The transmission filter minder cannot be reset like the engine oil life monitor.
If the transmission is replaced, customers will need to keep track of the mileage, starting with the first 7,500-mile (12,000-km) maintenance service for the new transmission.
Transmission Fluid and Filter Information in the Owner’s Manual
In addition to the maintenance minder, customers should be reminded to follow the transmission fluid and filter change recommendations in the Corvette Owner’s Manual. The Owner’s Manual includes the following information:
Transmission Fluid Change
When the CHANGE TRANSMISSION FLUID SOON message displays, change the fluid and filter within the next 600 miles (1,000 km). Failure to change the transmission fluid at required intervals can lead to reduced transmission performance. The transmission fluid must be changed at least every three years, and the Fluid Life System must be reset.
Check the transmission fluid life percentage. If the percentage is less than 10%, replace the fluid and filter. The initial transmission canister fluid change must be performed at 7,500 miles (12,000 km), and every 22,500 miles (36,000 km) thereafter.
If the canister filter is replaced more than 500 miles (800 km) prior to the initial 7,500-mile (12,000 km) break-in period, the filter still needs to be replaced again within plus/minus 500 miles (800 km) of the 7,500-mile (12,000 km) service interval.
Transmission Fluid
The DCTF FFL-4 C8 Corvette transmission fluid should always be shaken vigorously prior to adding fluid to a vehicle in order to disperse the additives throughout the fluid. The fluid has a shelf life in the bottle of three years. (Fig. 6)
Dealership FAQs
If a customer decided to replace the filter early, they still must replace it again at 7,500 miles. What is a customer to do if they went until 8,100 miles because they could not make it in? Are they just out of warranty now or do they have to pay for two filter replacements at that time and then the warranty is good?
Changing the canister filter at 7,500 miles was defined as the initial break-in of the transmission components and a period when the most contaminants may be created. Engineering expects the filter to be changed as close to 7,500 miles as possible. Plus/minus 1,000 miles should not be detrimental. If the filter is changed any earlier, say at 3,000 miles, it should be changed again at 7,500 miles as directed. If a transmission is replaced due to failure, the customer should restart the filter maintenance as if it was a new vehicle and the next filter change should be at 7,500 miles after replacement. If the customer fails to change the filter in a timely manner, such as missing the 7,500-mile maintenance interval altogether, and are now at 10,000 miles, the proper repair would be to not perform the flush procedure prior to the first filter replacement. Performing the flush procedure with a possibly overloaded filter would only push debris back into the system. The filter should be replaced first, followed by the flush procedure, and then a second filter should be installed. GM will only pay for the first filter replacement at 7,500 miles. Any additional filters and labor will not be covered.
If we get a vehicle with a porous case and the customer did not replace the filter on time, is their warranty blocked? If a customer bought a used C8 and the previous owner did not replace the filter on time, are they out of coverage? Can we perform the hydraulic system flush procedure and replace the filter twice and then they are good?
Transmission case porosity issues will not be affected by a lack of maintenance. GM cannot control what previous owners do when it comes to maintenance. Customers can ask dealers or the previous owner to review the maintenance history on a newly purchased used vehicle. If there is not a history of maintenance record, the proper repair would be to not perform the flush procedure prior to the first filter replacement. Performing the flush procedure with a possibly overloaded filter would only push debris back into the system. The filter should be replaced first, followed by the flush procedure, and then a second filter should be installed. GM will only pay for the first filter replacement at 7,500 miles on a new vehicle. Any additional filters and labor will not be covered. A transmission that is already having symptoms or setting codes will not be repaired with the change of the canister filter. Lack of maintenance by the previous owner may void the transmission warranty. Dealers selling certified used vehicles need to verify that all needed maintenance is performed prior to sale.
Track Fill Information
M1L Transmission and Z51 RPO – Vehicles equipped with M1L transmissions and Z51 models will need an additional two liters of transmission fluid added before track use. Transmissions will need to be identified as Die 1, Die 2 or Die 3.
GM does not condone tracking M1L-equipped vehicles without the Z51 RPO. If a customer decides to track the vehicle anyway, the transmission will need an additional two liters of fluid added before track use.
M1M Transmission – Vehicles equipped with M1M transmissions do not require a track fill with additional fluid.
Die 3 Cases – All vehicles equipped with either M1L or M1M transmissions and Die 3 cases do not require a track fill with additional fluid.
– Thanks to Marty Leach
Source:
GM TechLink via MidEngineCorvetteForum.com
Related:
GM Issues Techlink Article in Response to C8 Corvette Headlights Coming on During the Day
Some 2023 Corvettes Were Built with the Wrong Suspension Calibrations
Here is How To Fix Those Brake Pulsations and Grinding Sounds on C8 Corvette’s Equipped with Z51
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Wonder if Ferrari or Lamborghini have this kind of maintenance? My good old Tremec M7 is easy to change the fluid. 3 quarts of Redline D4 ATF and 30 minutes of my time.
I decided at 1,100 miles to change the DCT Filter and have “A Complete Flush of the Transmission” and Added the Additional 2 Liters of Transmission Fluid to the Z51 C8!
I was concerned about the debris and had been hearing all the Trouble Owners had with Transmission Issues.
Yes, it was EXPENSIVE, but it gave me more confidence and peace of mind that I was doing Preventative Maintenance.
A Wise Corvette Person told me: ‘If it’s a Fluid, it’s never too early to change it!’
I agreed with that!!!
I can’t believe they have made this so complicated! A person with an average command of the English language should be able to explain how to do these procedures so the common person could understand. What an embarrassment.
How do you know which transmission you have – ML1, MLM, Die 1,2,3 ??
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