7 Speed DCT Vs 8 Speed TC Gearbox

Faults and Technical chat for the Volvo XC40
JFDIT
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Joined: Tue Sep 28, 2021 5:21 pm

Post by JFDIT »

Had anybody been able to compare the 7 and 8 speed gearboxes yet? Views on how the 7 Speed drives? Similar to the VW group DCG?
XC40 MY24 B4 Ultimate Dark, Black Leather, Crystal White, 20" Rims
Lincolnshire England.

hotfrog
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Joined: Tue Jun 22, 2021 11:26 am
Location: Longfield Kent UK

Post by hotfrog »

I can only speak about the seven speed box as I have nothing to compare it to.

I have had the car for three months and done 3450 miles. The gearbox is excellent and generally very smooth. The gear changes are hardly perceptible. It has two slight issues. 1. For the first couple of changes from 1st to 2nd gear there is a slight hesitation after a cold start, once that is over it is fine. 2. When coming to rest the downshift from 2nd to 1st sometimes gives a tiny mini push that is very slightly disconcerting but once you learn this, no problem. From what I have read the throttle is blipped on downshifts to match the speed, it may be this that gives the effect when stopping. Overall I am very happy and it very good at its job.
XC40 R-design B4 FWD 7 speed. Ordered 14/10/21 Delivered 13/1/22
Pilot Assist, 360 deg cam, Panoramic roof etc.
Deleted User 3629

Post by Deleted User 3629 »

Having driven older TC's, then DSG's for many years, and now back to a modern TC - the biggest difference is hesitation at pulling away with a DSG and when reversing on a slope with a DSG - DSG's can often be more fragile too with expensive repair costs reported at relatively low mileage - overall I did like the freshness of a DGS when they first arrived but on return to a TC, and on balance, realised very quickly that a TC is a more natural partner and a better automatic to live with.
Krystof
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Location: Czech Republic

Post by Krystof »

Having some experience with both, I'd say it feels very similar to the VW Group dual-clutch transmissions that I've driven. Both are nice and smooth.

I think in general, whether a driver prefers a TC or a DCT is partly down to personal preference, and partly down to what they're used to. I came to DCTs after decades of driving manuals, so for me they always felt like a kind of improved manual system, and personally I prefer them over TCs because to me, DCTs feel somehow "sharper". But on the other hand, people who are more used to TCs often don't get on with DCTs. The two types of transmissions behave quite differently, and that can take some getting used to if you're expecting them to be similar. Particularly, as Oldie says above, DCTs will usually have some hesitation if you try to pull away quickly, which can be irritating until you get used to it. Also, with a TC the creeping forward is a natural feature of the system, so some drivers who are used to TCs will let a DCT do the same - but that will damage the clutch pack in the long run, just like regularly riding the clutch in a manual. So all in all, I think both types have their pros and cons, and it's really a case of different strokes for different folks.

As far as durability is concerned, historically the problematic DCTs have been dry-clutch systems, which had a tendency to overheat. (That was the case with some early VW and Ford ones.) Some manufacturers are still persisting with dry-clutch systems (which are cheaper), but the Volvo/Geely DCTs are all wet-clutch systems, which by all accounts are much more durable. To be honest I don't think there's any reason to worry about the durability of any manufacturer's modern wet-clutch DCT system - if I ever hear about a problem with a DCT system, it's always a dry-clutch box.
JFDIT
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Joined: Tue Sep 28, 2021 5:21 pm

Post by JFDIT »

@Oldie, have you driven the XC40 7 Speed DCT?
XC40 MY24 B4 Ultimate Dark, Black Leather, Crystal White, 20" Rims
Lincolnshire England.
Deleted User 3629

Post by Deleted User 3629 »

My expression of preference is not as a criticism of the alternative. DSG boxes are manuals gearboxes that shift automatically, and as such, they behave more characteristically closer to a manual - but having driven both and back again to a modern TC, my preference is the TC because of its more relaxed driving character - have not driven the geely's 7-speed DCT, and from article's read, seems to be a good gearbox with the potential to be more reliable than VW's DSG - but as Krystof says, that's probably down to it being a wet-clutch system then a dry one. However, if I had the choice of both to drive I would choose the TC because of its differing character over a duel-clutch system, a preference, that's all.
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Greggspies
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Post by Greggspies »

The question of hesitancy in DCT boxes when moving off is resolved in hybrid cars (whether mild, self charging or plug-in) because it's the electric motor that kicks the car into motion and that is instantaneous.
MY22 T5 Recharge Inscription Pro in Denim Blue with Blond Interior
Richard_Hants2
Posts: 4
Joined: Tue Jan 25, 2022 3:25 pm

Post by Richard_Hants2 »

I have had a B4 with the 7-speed DCT gearbox since early January and prior to this my previous 3 cars were VW's all fitted with DSG gearboxes.

The most obvious differences when driving the XC40 is the lack of hesitancy when pulling away (its very responsive) and also that when the engine has turned itself off it restarts so quickly that you soon learn to just trust it will go as soon as you touch the accelerator.
MY22 B4P R Design 7 sp DCT, Thunder Grey with Climate, Park Assist, 360 Camera, Wireless Charging and Spare Wheel.
Felindre
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Joined: Wed Dec 23, 2020 2:19 pm
Location: South Wales, UK

Post by Felindre »

To be fair you can't compare the start stop on a B4 to the VW's, a totally different ball game. The Volvo's used to have the same SS system as VW, and there are loads of complaints on here. The B series is a 48 volt battery and large motor generator belt driven off the engine dedicated to the starting, and works superbly. it's also supposed to give a helping hand at moving off, hence the 'mild hybrid'
B4 AWD Inscription , Fusion Red, Blond interior. Drivers Assist, Climate, Tinted rear windows and Towing pack.
Ordered 14 Dec 20, delivered 10 March 21
Deleted User 3629

Post by Deleted User 3629 »

Yep, the 7-speed DCT sounds like an OK gearbox, but again my preference is the TC - the XC40 was originally designed with the TC gearbox, its a gearbox that is fitted to many a top marque and in my opinion suites the relaxed style of the Volvo marque too, whereas the duel-clutch in my view is positioned more towards a manual experience and have read it's a gearbox fitted to Protons???
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