Hi All,

Posted this earlier but it seems to have disappeared so please fogive me if it still out there. First automatic car after many years of manuals. Advised to put car hand brake on during prolonged;statiomary periods when in 'D' ie traffic lights. Doing this sets parking brake warning chime off. According to manual chime is only supposed to sound if parking brake is on and car reaches 3 mph. As the car is stationary why is this happening as the car is not moving. I suppose I could turn warning chimes off but not a good idea. Any suggestion of possible fault or is this supposed to happen on an automatic?

ONLY put the handbrake on and take your foot off the brake if you are in neutral or park.

Keep your foot on the brake in D, stop/start should kick in on that anyway

Different auto's are setup in different ways.  You can't assume info from one will be correct for another.

As the Fiesta has a manual handbrake and no auto-hold, I agree with Dave, only use the handbrake in N or P.

When driving an auto (which are predominantly dual clutch these days), I still tend to apply the "handbrake"  and slip it into neutral for a prolonged stop, just as I would with a manual.

During accompanied test drives, I've often had sales staff say there's no need, just leave it in D and keep your foot on the brake. I still see this as bad practice on a dual clutch box as to me it's the same as holding the clutch down for an extended period on a manual. Or am I just old fashioned?😀

33 minutes ago, Eric Bloodaxe said:

Or am I just old fashioned?

Yes 🤣

Many thanks for the answers above which I shall take on board and follow your instructions. I must admit I am very impressed with the smoothness of the box and should have got an automatic a few cars ago.

6 hours ago, Eric Bloodaxe said:

When driving an auto (which are predominantly dual clutch these days), I still tend to apply the "handbrake"  and slip it into neutral for a prolonged stop, just as I would with a manual.

During accompanied test drives, I've often had sales staff say there's no need, just leave it in D and keep your foot on the brake. I still see this as bad practice on a dual clutch box as to me it's the same as holding the clutch down for an extended period on a manual. Or am I just old fashioned?😀

Old fashioned or not, If I stop the car it goes into neutral. 

I too would put it in neutral if I was expecting to be stopped for more than a few seconds. 

On a DCT, when you hold your foot on the brake, in D, the clutches release.

If you hold the car in D on the handbrake, you are effectively fighting the clutches against the handbrake. BAD

In a torque converter auto the same sort of applies, but not as severe as on a DCT

Where you say the clutches release I take it that means declutching ie. The same as holding your foot down to the floor on the clutch pedal on a manual car.   ie causing excessive wear to the clutch release bearing. Have I understood that correctly.   I can’t say I know how long a clutch release bearing might last in these circumstances but if it was my car I wouldn’t do something that I know is causing needless wear and possible earlier failure. 

53 minutes ago, isetta said:

ie causing excessive wear to the clutch release bearing.

Maybe - but using the same analogy, it reduces wear on the clutch friction surfaces.  So given the swings and roundabouts, I'd go with the designer/manufacturer's guidance.

But if I put it in neutral there won’t be extra wear on the release bearing or the clutch plate friction linings

As Dave and some others have said, definitely on the Getrag Powershift DCT450, it does not need to be placed into neutral when the veh is stationary as it automatically goes into neutral/auto disengagement mode.

Here is an actual extract from the 100 odd page factory Getrag Powershift Operating Manual that I have

Neutral control
This is a function that is activated when the driver stops and the vehicle is stationary, e.g., at a red light.
The TCM disengages the clutches, which means that the transmission's forward drive is reduced, as
well as the engine load.
The function reduces both fuel consumption and vibrations. When the driver releases the brake, the
clutch torque increases on the clutch for which the gear is engaged, and drive increases.
The following conditions must be met in order for the neutral function to activate:
· gear lever in D or R.
· throttle position 0%
· brake pedal pressed down.
· speed 0 km/h.
 

47 minutes ago, TrevorB said:

The TCM disengages the clutches, which means that the transmission's forward drive is reduced,

Note the word "reduced", not "removed".  It's not quite the same as completely depressing the clutch in a manual car.

Just a play on words I think Alan, remember it is not a uk manufacturer - workshop tests confirm there is no attempt to drive by the trans when the above is followed.

Also another, but basic test, when your foot is on the brake and speedo at zero, if you then move lever to N or P the engine revs do not increase one "iota", again indicating there was no connected drive mode dragging between eng and trans

As others have said, the worst thing to do is to leave it in D or R and put H/B on with foot off the brake - then it really is still in drive mode

13 hours ago, alanfp said:

Note the word "reduced", not "removed".  It's not quite the same as completely depressing the clutch in a manual car.

That means that the gearbox is still holding first gear for you for when you take your foot off the brake, to pull away. But the clutches are held off by the release motors, there are no release bearings on a DCT

In neutral the gearbox disengages first gear too, so you have to wait for clutches to disengage and gearbox to select first gear and the clutches to reengage before you can pull away.

I note Dave says there are no clutch release bearings on a DCT. I don’t know how a dct works exactly (well roughly speaking I think it’s like a manual gearbox and clutch and a load of computerised electro mechanical stuff changes gear and operates from clutch(Es) for you.  But how can the clutch declutch without a release bearing. I’m not saying Dave is wrong, I just want to understand how it works, although it might be beyond me without a cutaway moving model. 

1 hour ago, isetta said:

I note Dave says there are no clutch release bearings on a DCT. I don’t know how a dct works exactly (well roughly speaking I think it’s like a manual gearbox and clutch and a load of computerised electro mechanical stuff changes gear and operates from clutch(Es) for you.  But how can the clutch declutch without a release bearing. I’m not saying Dave is wrong, I just want to understand how it works, although it might be beyond me without a cutaway moving model. 

It's all done by magic!   Once you've accepted that, life become a lot less anxious 🙂

Isetta, you are correct, Dave is NOT wrong.

Don't want to put myself out on a limb here but if anyone is interested in some bedtime reading of "How the DCT450 Works" I will send you the 100+ pages operating manual (It does not tell you how to diagnose probs or how to repair or strip rebuild it)

I can't put it up on here so anyone will have to PM me their own private e mail address so I can send them the document as an attachment

12 hours ago, TrevorB said:

Just a play on words I think Alan, remember it is not a uk manufacturer - workshop tests confirm there is no attempt to drive by the trans when the above is followed.

Also another, but basic test, when your foot is on the brake and speedo at zero, if you then move lever to N or P the engine revs do not increase one "iota", again indicating there was no connected drive mode dragging between eng and trans

That sounds right.  But then why does my fuel consumption increase from 0.1 gal/h to 0.2 gal/h when I engage D or R with my foot on the brake?  Knowing that this is what happens (and I've just been out to my car to double-check this - how sad am I !!!) I was so relieved to see the statement using the term "drive is reduced". But now I'm all confused again.

I think I ought to take my own advice and stop thinking about it 😉

I would very much doubt those two figures are a million per cent correct anyway - its all done via algorithms

Drive on and enjoy

I think it is  about time I apologised for starting this topic. What I thought was a simole question has turned out ito be not quite an argument but a heated discussion. SORRY

Who knew that there were so many people driving an Automatic incorrectly 🤔

I'll leave it up to the individuals to decide what the correct method is 🤣

2 hours ago, jsk said:

I think it is  about time I apologised for starting this topic.

No need, John. All this has served as a useful reminder of why I've been perfectly happy with three pedals these last 50 years or so!😃

23 minutes ago, Eric Bloodaxe said:

No need, John. All this has served as a useful reminder of why I've been perfectly happy with three pedals these last 50 years or so!😃

Oh God no!

I'd never have a manual again as long as I can drive, but I'd never have another Ford auto again

ZF are the best