Automatic gearbox and regular use of neutral

Advocado

I have a 2019 VW with an auto gearbox.  When I take my foot off the accelerator, there is quite heavy engine braking - going down a steep hill and it will still lose speed.

But popping it into neutral and it'll coast for what feels like forever.  And by doing so regularly, my mpg improves massively - around 45 mpg instead of 33-36mpg.

But does this do any harm to the gearbox?  I'm assuming not because, in this world of computers, I'm guessing it wouldn't let me do anything that would cause any damage, but wanted a second opinon.

mobileron

Surely it would be classed as not in charge of the vehicle ie coasting.
As its a VW is it a dsg box?

daveyjp

DSG boxes are so flaky driving it without slipping into neutral and coasting is more than enough to cause serious damage.

Advocado

mobileron said:

Surely it would be classed as not in charge of the vehicle ie coasting.
As its a VW is it a dsg box?

Not sure, but a quick Google suggests VW use DSG automatic gearboxes, so I'd assume it is.

Advocado

daveyjp said:

DSG boxes are so flaky driving it without slipping into neutral and coasting is more than enough to cause serious damage.

So I'm doing the right thing?

Keep_pedalling

Advocado said:

daveyjp said:

DSG boxes are so flaky driving it without slipping into neutral and coasting is more than enough to cause serious damage.

So I'm doing the right thing?

No, I think Dave may have mis-worded his statement. 

What model VW is this? 

neilmcl

Advocado said:

I have a 2019 VW with an auto gearbox.  When I take my foot off the accelerator, there is quite heavy engine braking - going down a steep hill and it will still lose speed.

But popping it into neutral and it'll coast for what feels like forever.  And by doing so regularly, my mpg improves massively - around 45 mpg instead of 33-36mpg.

But does this do any harm to the gearbox?  I'm assuming not because, in this world of computers, I'm guessing it wouldn't let me do anything that would cause any damage, but wanted a second opinon.

It's called engine braking and it's exactly what you should be doing to control your speed. Coasting like this is not recommended and means your not fully in control, and I'd especially wouldn't recommend it with a DSG gearbox as you could damage the mechatronic.

BOWFER

It'll be a DSG for sure.
I've had two, an Audi A3 2005-2008 and a Polo GTi 2020-2021.
If the OP is using 'D' then there really shouldn't be much engine braking at all and I cannot for the life of me see why his MPG would be improving dramatically.
It's not like foot off the throttle in gear is using fuel.
Heavy engine braking going down steep hills isn't normal for 'D' , I often go down steep hills and the car would speed up.
I then had to use the brakes (obviously) or use the paddles to manually select a lower gear.

neilmcl

Agree with the above, coasting in gear shouldn't use any fuel, in fact you should save fuel due to engine braking regeneration, whereas being in neutral wastes fuel because the engine will be idling.

Advocado

BOWFER said:

I cannot for the life of me see why his MPG would be improving dramatically.
It's not like foot off the throttle in gear is using fuel.

My mpg improves because the vehicle goes further without using any fuel.  If it's in D it slows down fairly quickly so I then need to press the accelerator again to maintain a decent speed.

Maybe I exaggerated slightly with "steep hill", but anything less than what you would call steep and it loses speed.  And on the flat, it'll go from 40mph to 30mph in about 10 seconds when in D.  In N it probably takes nearer 45 seconds.

Advocado

BOWFER said:

I cannot for the life of me see why his MPG would be improving dramatically.
It's not like foot off the throttle in gear is using fuel.

My mpg improves because the vehicle goes further without using any fuel.  If it's in D it slows down fairly quickly so I then need to press the accelerator again to maintain a decent speed.

Maybe I exaggerated slightly with "steep hill", but anything less than what you would call steep and it loses speed.  And on the flat, it'll go from 40mph to 30mph in about 10 seconds when in D.  In N it probably takes nearer 45 seconds.