drive question in automatic

[Shallow Al]

It's a good question. I suppose it depends what is slipping when you are stopped.
Is it one of the clutches slipping? or as I suspect, it is the torque converter slipping, or "giving".
If it's the t.c. It's doing what it should as its a fluid coupling.
Need an auto box expert.

[robson]

How long have we been driving these cars and it appears that nobody knows the answer to a simple question and that includes me

[McBandy]

I agree completely, about not holding the car on the footbrake, Baza - it will definitely cause disc warping and subsequent brake judder, but I was wondering about the possible downside to holding the car on an incline in Drive and without brakes applied - you know, being lazy!
Will this result in any problems long-term?

Ron.

Given the right hill I sometimes do this in the Scanias and I don't believe it causes undue stress, surely it's easier on the 'box than having to move off from stationary?...

[Steve B]

How long have we been driving these cars and it appears that nobody knows the answer to a simple question and that includes me

Ive only just found out that if you have your foot on the gas pedal at say 30mph and then put your other foot on the brake then the engine sort of shuts down

[Bigron]

Isn't that the Stall Test, Steve? I seem to recall reading something, somewhere (on here?) to that effect.

Ron.

[Entwood]

Isn't that the Stall Test, Steve? I seem to recall reading something, somewhere (on here?) to that effect.

Ron.

Proper Stall Test procedure here ..

http://etereman.com/blog/transmission-care/transmission-troubleshooting-techniques-properly-perform-a-stall-test

or

http://www.freeasestudyguides.com/torque-converter-stall-test.html

but NEVER exceed 5 seconds ....

[frostbite]

Modern slushboxes should have a neutral stop feature. Where it selects neutral after a few seconds of being stopped, volvo had this but it just destroyed the boxes

Im not sure our dinosaur boxes have this feature

[Bigron]

Thanks Nige - at least it showed that I wasn't dreaming it!
My caravan is happy to be home, thanks to you.

Ron.

[Andy B]

Modern slushboxes should have a neutral stop feature. Where it selects neutral after a few seconds of being stopped, volvo had this but it just destroyed the boxes

Im not sure our dinosaur boxes have this feature

SWMBO had an auto Astra G that did that, you had to wait a second or so for it to take up drive after you'd released the brake .... IMHO it was awkward

[Andy B]

Isn't that the Stall Test, Steve? I seem to recall reading something, somewhere (on here?) to that effect.

Ron.

Proper Stall Test procedure here ..

http://etereman.com/blog/transmission-care/transmission-troubleshooting-techniques-properly-perform-a-stall-test

or

http://www.freeasestudyguides.com/torque-converter-stall-test.html

but NEVER exceed 5 seconds ....

A stall test is different from what frostbite was describing. I've notice what frostbite has noticed, it feels as though the fly-by-wire throttle is turned off if you press the brake enough for the brake lights to come on for more than a few seconds

[steve6367]

I have often wondered how long one should leave an automatic Omega in drive for when its standing in traffic?

Do you simply put your car in drive in the morning and leave it there all day sort of thing, or what?

Also what actually is happening wear wise, in the gearbox when its left in drive ?

   

Mine stays in D once I'm underway - it the TC slipping and compared to the energy and heat it has to dissipate when you floor it sitting still is nothing. I do however use the handbrake so as not to blind those behind me.

[Kevin Wood]

Yep, DBW cars cut the power if you have both throttle and brake applied for more than a couple of seconds.

I would say take it out of drive in any circumstances where you'd take a manual out of gear. Mechanically, it matters little. Clutches in an auto box are either fully engaged or not. They die very quickly if they "slip". The torque converter is the component that takes up the drive and that is not a wear item. It will heat up the fluid rapidly if you use it to hold the car on an incline, mind, so best to use the brakes until you have to move away.

[DrAndyB]

Yep, DBW cars cut the power if you have both throttle and brake applied for more than a couple of seconds.

As my Omega is a manual then there is no problem   

However, the wife's car, new VW Touran 2.0 TDi DSG Auto definitely cuts the drive power if you stop and press brake pedal down.  Slight drop in rpm and stops creeping.  The moment you even think of coming of the brake and slightest release of pressure on brake pedal then it increases revs ever so slightly and if on a hill automatically holds it until you press the loud pedal, to which slightest press and pulls of nice and easy with no roll and a definite feel of it being held at the rear on the brakes.  All cleverer stuff and improvement on the previous DSG we had which rolled back slightly just before transmission wound itself up !!  Goes like a stabbed rat and has same bhp as my 2.5 V6 Omega