How long can you sit stationary in drive on an automatic

[Deletedmember53506]

With the ever increasing traffic jams and more automatics now than ever I was wondering how long people sit in drive rather than neutral/park when in traffic jams.

My limited knowledge of auto gearboxes leads me to believe that it wouldn't take too long (minutes maybe) to overheat a torque converter.

Do modern cars have temp sensors/cooling in the gearbox etc or does the problem just not occur in modern boxes? My last (limited) experience of an automatic was over 15 years ago so I guess things have changed a little

p.s. when I say limited it ammounted to opening up one and then deciding to get a gearbox specialist in after realising I couldn't name half the parts in there let along try and fix it

 

[markjay]

The general advice is not to shift auto autobxes in and out of D while in stopped traffic, due to risk if increased wear.

Most people will keep the car in D and simply use the brake pedal, but what you should really do is use the parking brake and let go of the brake pedal.

Not sure about torque conevrter overheating or heat sensors though.

 

[Tonison]

I usually shift between D and N to reduce wear on the brake pads. But I'll rather reduce wear on my gearbox after reading the above post.

 

[Dryce]

I usually shift between D and N to reduce wear on the brake pads. But I'll rather reduce wear on my gearbox after reading the above post.

Do the brake pads wear when the car is stationary?

 

[Tonison]

Yes, when in D.

 

[John Kerr]

Do the brake pads wear when the car is stationary?

There is a risk of warping the discs over time.It has happend to me with a W203 c Class.I thing the heat builds up under the pads

 

[Tonison]

That's also true, when stationary for more than a couple of minutes I'll be inclined to shift to N.

 

[renault12ts]

Yes, when in D.

How could they possible wear out when they are merely pressed against the discs and the car is standing still...have you thought this through?

 

[Roamer]

Hmmm, i've been going from D to N while stationary at lights, but based on this thread i'll stop doing that.

 

[renault12ts]

There is a risk of warping the discs over time.It has happend to me with a W203 c Class.I thing the heat builds up under the pads

If you have been doing some quick cross country driving applying the brakes a lot and then are faced with a traffic jam this might (though I don't believe it) happen.

But driving in stop start city traffic this will not happen.

Having driven for 35years, I have never had warped discs.

 

[renault12ts]

Hmmm, i've been going from D to N while stationary at lights, but based on this thread i'll stop doing that.

Good idea. It's also more relaxing, on and off the brake pedal to move stop and move forward. Its an auto after all, why use the shift like a manual?

 

[Tonison]

How could they possible wear out when they are merely pressed against the discs and the car is standing still...have you thought this through?

Yes and even practically. Try switching to D, release all brakes, and without pressing down on the gas pedal to see for yourself.

 

[renault12ts]

Yes and even practically. Try switching to D, release all brakes, and without pressing down on the gas pedal to see for yourself.

The car moves forward. So the brakes will not wear.

But you maintain that the brakes will wear if you are sitting still with the brakes applied and the box in D. How? Where is the moving friction between the discs and pads which would provide wear?

 

[JonathanC250]

Yes and even practically. Try switching to D, release all brakes, and without pressing down on the gas pedal to see for yourself.

HA! Yes the car will move, your talking about shifting to nuetral then rolling to a stop.

But the OP is talking about once stopped, once the car has stopped on the brakes, no more wear, as there is no movement.

 

[NormanC]

Yes and even practically. Try switching to D, release all brakes, and without pressing down on the gas pedal to see for yourself.

Absolutely NO!!!

Pads can only wear when there is relative motion between the pad and the disc, i.e. you are moving.

If this were not true then your tyres would wear out whilst you were parked!!

 

[JonathanC250]

When stopped in traffic for a while i shift to nuetral, for the same reason, i think this will cause less strain on the gear box and torque converter.

As i know hardly anything about Auto boxes, i am happy to be proved wrong.

Plus i used to do it, when my engine mounts went, as the car shuddered less in neutral!

 

[JonathanC250]

Absolutely NO!!!

Pads can only wear when there is relative motion between the pad and the disc, i.e. you are moving.

If this were not true then your tyres would wear out whilst you were parked!!

Hahaha, i like that!

 

[renault12ts]

When stopped in traffic for a while i shift to nuetral, for the same reason, i think this will cause less strain on the gear box and torque converter.

As i know hardly anything about Auto boxes, i am happy to be proved wrong.

Plus i used to do it, when my engine mounts went, as the car shuddered less in neutral!

No need to worry, the Tc is designed to be used this way...leave it in D. Unless you know you'll be there 10 minutes...then put in N, apply parking brake and relax. Otherwise keep in D and use the foot brake to move forwards when you need to.

 

[Tonison]

Why do you need the brakes in D? When breaks are applied in D, isn't there resistance against the brakes?

 

[renault12ts]

Why do you need the brakes in D? When breaks are applied in D, isn't there resistance against the brakes?

Are you being serious, or winding me up?