Footbrake/Handbrake in Drive on Automatic

[maderic]

Sorry if this has been asked before. I’m well aware that using the footbrake leaving an auto in drive will blind people behind. My question is specifically about whether holding the footbrake in drive is bad for an auto transmission. This leads on to next question whether it’s ok to Leave the handbrake on in drive or if you’re employing the handbrake should you knock it into neutral

Many thanks

[Mars]

Does no harm at all. An auto torque converter will just sit their idling, get to a certain (in tolerance) temperature, and deal with it.

[TheAngryDog]

That is some lurking! Thirteen and a quarter years!

[Alex_225]

It really depends how long you're going to be sitting there for but as I understand most autos will be perfectly fine sitting using the brake to stop you rolling. If I'm sat in traffic or know when the lights will change I'll pop the car in neutral.

I have a hold button on my S Class which holds it on the brakes without keeping my foot down, it keeps it in drive though so I assume it's not problematic to do the same.

Hope that helps.

[littleredrooster]

The manufacturer ZF specifically says not to use neutral when at a standstill. Leaving it in D is fine, footbrake or parking brake - your choice.

[LeoSayer]

Fine for non-torque convertor autos eg. DSG, CVT etc.

Pressing the brake pedal at rest usually causes the clutch to be disengaged, preventing clutch wear.

I try to avoid riding the brake pedal to slow down the rate of creep. Otherwise the clutch will be constantly slipping.

[thewarlock]

For a 'real' auto, a torque converter, you shouldn't really leave it in neutral, it'll wear out the front clutch pack.

[RicksAlfas]

Leave it in D.

[yellowbentines]

Leave it in D, use the footbrake or auto hold feature if there is one. That way when it's time to move off you can do so swiftly without delay, keeping traffic and therefore society moving, and contributing towards a strong economic recovery.

Nobody will be blinded. Some people will say they are being blinded, but they really aren't, they'll be just fine.

[honest_delboy]

TheAngryDog said:

That is some lurking! Thirteen and a quarter years!

Surely that's got be some sort of PH record ?

[PH User]

Blinded by a brake light??

[juice]

PH User said:

Blinded by a brake light??

Revved up like a deuce
Another runner in the night

[Krikkit]

thewarlock said:

For a 'real' auto, a torque converter, you shouldn't really leave it in neutral, it'll wear out the front clutch pack.

Not disagreeing, but can you elaborate on this? Seems odd for a clutch to be slipping while in neutral.

[thewarlock]

Krikkit said:

Not disagreeing, but can you elaborate on this? Seems odd for a clutch to be slipping while in neutral.

I can certainly try.

The main difference between neutral and park is that when in park, there's a mechanical internal gearbox brake.

If you're in drive, and stop, the main forward clutches are engaged, and the TC is providing pressure to rotate first gear, but it doesn't rotate, because the gear is engaged and connected to the (stationary) wheels.All of the slip is occurring in the TC

In neutral though, with the engine turning and the wheels stationary, the TC is providing rotation, as you're not in a gear, the wheels aren't keeping the gearbox internals for rotating, so some of the slip is happening in the clutch pack, some is still being taken by the TC. It's a bit like, in a manual, holding the handbrake, whilst being in 1st and lifting the clutch a bit, slipping it constantly.

I think. Far from an expert, auto boxes have always been a bit of a mystery to me.

I should add, an auto transmission expert explained it to me once in great detail, which is why I said it, yet struggle to back it up slightly

Edited by thewarlock on Wednesday 3rd March 17:03

[maderic]

Thanks. Isn’t leaving the auto in drive and using either handbrake or foot brake to prevent creep the same as having a manual around the clutch point ready to go and hence damaging the clutch?

[csd19]

No as it's the TC that's (internally) moving so it's transmission fluid giving some resistance.

If you then opened the throttle but held the car on the brakes you'll reach the stall speed on the converter (which isn't particularly high), holding it like that will begin to cook the trans fluid.

[OllieJolly]

maderic said:

Thanks. Isn’t leaving the auto in drive and using either handbrake or foot brake to prevent creep the same as having a manual around the clutch point ready to go and hence damaging the clutch?

No, because it works by moving transmission fluid, and that fluid is under a heck of a lot more stress/strain when accelerating than with the engine idling.

[raspy]

maderic said:

Sorry if this has been asked before. I’m well aware that using the footbrake leaving an auto in drive will blind people behind. My question is specifically about whether holding the footbrake in drive is bad for an auto transmission. This leads on to next question whether it’s ok to Leave the handbrake on in drive or if you’re employing the handbrake should you knock it into neutral

Many thanks

Not every car. Some cars have brake lights which reduce in intensity at nightime when stopped whilst foot is on brake pedal.

[shambolic]

I just push the brake harder and take my feet off then as it’s on Hold (MB).
Just touch the accelerator or tap brake again to disengage and move on.

[shambolic]

If I’m in a queue for ages I will put on the handbrake until ready to go again but not needed in normal day to day driving.