XC40 gearbox

Faults and Technical chat for the Volvo XC40
Felindre
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Post by Felindre »

I'm separating out this discussion so as not to keep diverting on the original thread...
Moss wrote: Wed Jul 21, 2021 10:49 pm
Felindre wrote: Wed Jul 21, 2021 8:25 am
Oldie wrote: Wed Jul 21, 2021 6:28 am Just throwing a thought out there - was your Tiguan automatic with the DSG box?

Having driven both, the DSG box is very different to the Volvo and doesn't disengage like a DGS - and these type's do tend to introduce more "drive motion" especially in slow/ stop start traffic.

Out of the two types I also feel that the Volvo auto box delivers a more relax drive and felt DSG boxes a little bit too snappy - great though for the more "sporty" drive's out!!

Also it's my understanding that the springs on the sport chassis should have a stiffer spring than standard - that's what was stated on 2020 built cars (MY21)?
I understood the Volvo box was also a dual clutch and virtually identical to the VW.
FYI
The Volvo XC40 8 speed automatic gearbox is an Aisin AXF8Fxx (or TG-81SC as Volvo calls it), also used by many other car manufacturers. Volkswagen uses it in the US version of the Tiguan.

https://en.wikipedia.org/wiki/AWF8F35
I've had conventional torque converter boxes in the past and more recently DSG. I thought it was DSG because the instant take up with no slippage, and the fact you can coast with it, which suggests it has to have a clutch to disengage. You also feel the 'clutch' engage as you come off coast.

The whole drive is just like my Tiguan was, and nothing like the Jaguar with the TC box.
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jamie307
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Post by jamie307 »

Torque converters have improved massively in recent times.
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Felindre
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Post by Felindre »

Agreed, But can't explain the coasting...
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Stanno
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Post by Stanno »

Felindre wrote: Sun Aug 15, 2021 2:41 pm Agreed, But can't explain the coasting...
Doesn't it coast in Eco drive mode?

Stanno
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Felindre
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Post by Felindre »

Stanno wrote: Sun Aug 15, 2021 2:55 pm
Felindre wrote: Sun Aug 15, 2021 2:41 pm Agreed, But can't explain the coasting...
Doesn't it coast in Eco drive mode?

Stanno
Yes, but how do you coast with a torque converter? This is what puzzles me about the statement that it's a regular TC auto box, as it's whole behaviour matches my experience of DSG's.
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Deleted User 3359

Post by Deleted User 3359 »

Felindre wrote: Sun Aug 15, 2021 11:47 pm

Yes, but how do you coast with a torque converter? This is what puzzles me about the statement that it's a regular TC auto box, as it's whole behaviour matches my experience of DSG's.
The B4/5 box is deffo TC, the T4/5 is DC... AS to not explaining the coasting, there would be many options... Clutch between TC and box to disengage, feather the TC, non-selectable neutrals etc...
Qarx
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Post by Qarx »

Pure ICEs and mild hybrids such as T4, D3, B4 and similar use torque converters
Plug-in hybrids (T4/T5 Recharge) use dual clutch
Pure electric P8 has no gearbox

Can be verified here under transmission and googling the transmission code: https://www.media.volvocars.com/global/ ... ifications
ciuncky
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Post by ciuncky »

Cornishman wrote: Mon Aug 16, 2021 8:59 am
Felindre wrote: Sun Aug 15, 2021 11:47 pm

Yes, but how do you coast with a torque converter? This is what puzzles me about the statement that it's a regular TC auto box, as it's whole behaviour matches my experience of DSG's.
The B4/5 box is deffo TC, the T4/5 is DC... AS to not explaining the coasting, there would be many options... Clutch between TC and box to disengage, feather the TC, non-selectable neutrals etc...
If i where to put my money on something, it'd be non-selectable neutral. Not from a mechanical point of view, but strictly from the feel of the car.
When stopped, if you have live fuel consumption in the dash you'll notice consumption is 0.4 gph, then drops to 0.3 and then to 0.2 in a matter of seconds.
While engine revs sit idle at 900, the only explanation of the lower consumption would be reduced load on the engine, which would suggest it somehow decouples from the TC?

Just an idea
ciuncky
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Post by ciuncky »

ciuncky wrote: Mon Aug 16, 2021 11:58 am
Cornishman wrote: Mon Aug 16, 2021 8:59 am
Felindre wrote: Sun Aug 15, 2021 11:47 pm

Yes, but how do you coast with a torque converter? This is what puzzles me about the statement that it's a regular TC auto box, as it's whole behaviour matches my experience of DSG's.
The B4/5 box is deffo TC, the T4/5 is DC... AS to not explaining the coasting, there would be many options... Clutch between TC and box to disengage, feather the TC, non-selectable neutrals etc...
If i where to put my money on something, it'd be non-selectable neutral. Not from a mechanical point of view, but strictly from the feel of the car.
When stopped, if you have live fuel consumption in the dash you'll notice consumption is 0.4 gph, then drops to 0.3 and then to 0.2 in a matter of seconds.
While engine revs sit idle at 900, the only explanation of the lower consumption would be reduced load on the engine, which would suggest it somehow decouples from the TC or most probably gets shifted to a Neutral?

Just an idea
Felindre
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Post by Felindre »

OK mine (B4 AWD) is AWF8G45, as you say, all documentation points to TC. I'm very impressed because all my previous TC's have had some slip when you boot it and the gearbox is in catchup mode, even when they had lockup on higher gears. This one has no detectable slip on foot down.
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Ordered 14 Dec 20, delivered 10 March 21
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