If you’ve been following the saga of the Corvette transmission issues you should know that the drumbeat has gotten loud. In fact, it is loud enough that GM has filed paperwork to look into the problems. C8 Corvette problems are littered with owners complaining about various issues since the Corvette was first released.
The Tremec TR-9080 eight-speed dual-clutch transmissions are leaking. They’re also flashing error messages. Owners are being instructed to put their Corvettes into Park and take it to the nearest Chevy service department.
GM says the Corvette C8 transmission issues are due to “debris”
In the filing with the National Highway Traffic Safety Administration, GM says some of the issues are caused by “debris on the park position sensor magnet causing an incorrect position reading to the transmission control module.”
Dealers are being told to have technicians remove transmission fluid at the 7,500-mile maintenance interval, according to GM Authority. GM then asks that the removed filter be saved. It wants techs to put it into a plastic container, being careful not to let too much fluid out of it, and return it to Chevy. GM engineers want to inspect the filters to see what might be gumming up the transmissions.
Of note is that forum members have said that the transmission pan and gasket have been redesigned for the 2021 Corvette. The older steel pan used two studs and 13 bolts. A new design changes it to an aluminum pan and 17 bolts. The gasket seats better in this design to lessen the chance it might squirm out.
Would a manual Corvette C8 transmission alleviate the issue?
One way to alleviate the problem would be to also offer a manual transmission option. We know that is being somewhat cute, but many enthusiasts are asking for the transmission. But GM has doubled down on there being no manual trans and has some reasons why it won’t.
Corvette Chief Engineer Tadge Juechter says that because there is an engine between the transmission and the shifter. That means there can’t be a mechanical linkage, so cable linkages are the only solution. He said that with cables, the shift feels “rubbery and vague,” in an interview on Autoline After Hours.
Nobody is buying manual transmissions anyway
Another big reason, and you knew this already, is that only a very small portion of buyers actually order the manual. As we’re seeing with more and more vehicles, the manual transmission option is being dropped. And this is the predominant reason automakers choose to eliminate it.
GM will shift TR-9080 manufacturing to the GM plant at St. Catharines in Ontario. The changeover should be completed by the middle of 2022. It mostly manufacturers aluminum cylinder heads and engine blocks for various GM products. TR-9080 manufacturing is currently outsourced to Tremec.