DCT Video Tour Component Explanation By Corvette Master Technician Paul Koerner

[John]

Walkaround and explanations thanks to the skilled Corvette Master Tech Paul Koerner.

The Corvette Mechanic Paul Koerner Does a Virtual Tour of the 2020 Corvette’s 8-Speed DCT Gearbox

By Keith Cornett



Earlier this week we brought you a virtual tour of the new 495-horsepower LT2 V8 engine by Key Chevrolet’s GM World Class Certified Technician Paul Koerner.

It’s only fitting for his next video that Paul next pulled up the new 8-speed dual-clutch transmission that will be offered exclusively on the 2020 Corvette Stingray.

Paul does another great job pointing out various aspects of the new DCT gearbox and then he uses a cut-away photo on a similar DCT to talk about how the transmission is able to accomplish those lightning-fast shifts with no drop of torque.

Later this month, Paul will be joined by Brittany Grande at Corvettes at Carlisle, and you’ll also be able to find the dynamic Corvette service technicians at the 25th Anniversary Celebration at the National Corvette Museum. So bring your Corvette-related questions about service issues and maintenance questions!


Source:
TheCorvetteMechanic / Facebook

[twowinns]

I’ve never owned or driven a car with a DCT. Does the car shift gears by itself, like a true automatic, or does the driver switch gears with paddles?

[Klinn]

Both. You can leave it in auto mode and it shifts by itself, or you use the paddles to shift yourself. Not sure if there's a true manual mode where it won't ever shift, even at redline, unless you pull a paddle. All depends on the programming GM sets up.

Oh yes, and welcome to the forum!

[twowinns]

Both. You can leave it in auto mode and it shifts by itself, or you use the paddles to shift yourself. Not sure if there's a true manual mode where it won't ever shift, even at redline, unless you pull a paddle. All depends on the programming GM sets up.

Oh yes, and welcome to the forum!

Thanks Klinn!

[RoketRdr]

Not sure if there's a true manual mode where it won't ever shift, even at redline, unless you pull a paddle. All depends on the programming GM sets up.

All the other DCT's in the market work this way so I'm assuming GM will do the same. Manual mode is completely manual except for extreme deceleration and coming to a complete stop. In those two scenarios it will downshift for you to keep from bogging the engine down or stalling. On upshifts you can bounce off the rev limiter all day long if you want to but it will also go into a "protection" mode if it sees that you're not making an effort to get off the limiter.

[meyerweb]

And it will probably be programmed to prevent you from over revving the engine by downshifting to 1st gear at 80 mph.

[electroVette]

Thanks. Great explanation video.

[meyerweb]

The key to the quick shifts in a DCT, which he sort of talked around but didn't come right out and say, is that 2 gears are always engaged at the same time, with the clutches keeping one active and the other not. So when you're accelerating in first gear, second gear is already selected, and all that happens when you "shift" is that the first gear clutch disengages while the 2nd gear clutch engages. Nearly instant shift. The computer will then select 3rd gear (without engaging that clutch) so when the next shift comes all you're doing, again, is disengaging one clutch while re-engaging the other. Ditto on downshifts. So programming the computer is critical, because if it guesses wrong about what gear you want next the shift will be slowed while the transmission selects a different gear than the one it pre-selected.

[Klinn]

So programming the computer is critical, because if it guesses wrong about what gear you want next the shift will be slowed while the transmission selects a different gear than the one it pre-selected.

Excellent point. If I'm braking for a corner with the expectation of nailing the throttle to power out the other side, upshifting as I go, but the computer thinks I'm going to keep slowing down and has preselected the next lower gear instead, there's going to be a delay while things get sorted out.

For me, I can see there will be a bit of a learning curve with the DCT in general, and with GM's chosen programming in particular. Which may vary depending on the driving mode you're using. This will be fun.

[meyerweb]

For me, I can see there will be a bit of a learning curve with the DCT in general, and with GM's chosen programming in particular. Which may vary depending on the driving mode you're using. This will be fun.

Good point about driving mode. That comment made me think of something else: If you have the PDR and are on a known (or learned) track, does the computer pay attention to where you are on the track, and whether you're downshifting into a corner, or about to come out of one?

That would be truly awesome, but I don't know if the tech is quite there yet.

[N4SPEED]

I’ve never owned or driven a car with a DCT.

Once you drive and get used to a DCT, you don't want to drive anything else. I had a C7 Z06 and loved it, however the A8 tranny was a disappointment. I am so looking forward to C8 with DCT!