OK - just so we’re all on the same page: A dual-clutch transmission looks exactly like an auto and you drive it, kinda like an auto, but it’s completely different down there, in the context of the mechanics of its operation.
They’re proliferating, too. The Volkswagen Group uses them. Hyundai-Kia uses them. They’re on the rise. Operationally, they’re more fuel efficient than conventional autos - so you’re saving 6-10 per cent on fuel there.
That’s like getting 10-15 cents per litre off, here in Shitsville. So it’s not insignificant. The tradeoff is: They’re not as refined as conventional autos - especially for low-speed maneuvering. They’re also more sporty to drive - but you can kill them quickly if you don’t know what you’re doing.
So I’m assuming you’ve driven a manual transmission at least once or twice: DCT’s are kind of like that, for taking off, except the clutch is automated.
(So instead of your left foot engaging and disengaging the clutch, when you take off or come to a stop, a computer makes the decisions and a servo motor does the heavy lifting with the parts.)
When you take off, going from stopped to about jogging pace, the automated clutch is engaging. (Just like in a manual.) So it’s both slipping and progressively gripping. You don’t control that - it just happens.
After about jogging pace, 12-15 kays an hour or something, the clutch is fully engaged (no slipping) and doesn’t function again until you next stop.
So, if you take off in a reasonably decisive way (like, keeping up in traffic when the lights go green) the clutch takes up over some seconds, it fully engages progressively and you drive off in first gear (and all subsequent gear changes - upshifts and downshifts) are automated and they happen without the clutch, because: technology.
However, if you inch forward very slowly, under load (like: uphill on a steep hill, at walking pace) the clutch won’t get the opportunity to engage fully (because you won’t be going fast enough for low rpm in first gear to sustain engine operation).
So it’ll have no alternative but to keep slip[ing, and when it does that under load it’ll rapidly generate heat and that will shorten its life. This is just like riding the clutch in a manual transmission - generally quite a bad idea, unless you like contributing to the dealer principal’s children’s exclusive private school education.
Just to be ‘crystal’ on this: it’s those two things together: Load and slip. This is the recipe for expensive repairs. It’s a choice, right? You can choose not to do it.
You can feel it when it happens. It won’t feel happy. So frankly, you’d have to be a bit of a moron not to form the view, fairly quickly, that this is a bad idea (especially after the first few goes - because there’s a clutch over-temp sensor and the car will beep flash a warning at you if you do this).
But having said that, some significant number of morons do manage to damage their transmissions in this way…
And this vulnerability - in my view - makes a DCT a poor transmission choice for towing, especially if that towing involves low-speed maneuvering under load, like reversing a trailer up a steep driveway, or tugging a heavy boat up a ramp.
For everyone else, basically, to avoid this problem you just take off moderately decisively in traffic and don’t allow the clutch to slip excessively by going really slowly under load. It’s not that hard to get this right in normal city driving - I know it sounds complex, but in practise it’s easy to avoid abusing the clutch in a DCT, just like it is in a manual.
Most DCT cars have hill-holder (type) functionality, which prevents roll-back, and you should use that because rolling back on a hill increases the load on the clutch dramatically as well.
Kindly note - this does not mean DCT clutches are intrinsically under-designed, or incompatible with hill starts, etc. They’re generally fine. Quite robust, even. You just have to use them properly. (Like every other machine that has ever been designed and rolled out into production.)
Angle grinders and circular saws aren’t dangerous, for example, unless you fail to heed, or understand, the risks. This is that.
One of the main problems is that, although cars are increasingly complex, car companies and the dealers selling them do not provide any training or other accessible, barely adequate information to help you digest all these operationally significant aspects of the vehicle you just dropped $40,000 on.
I guess you can find it on YouTube - but the challenge here is, of course, bullshit filtration. Good luck with that.