Will Automatic trans - with brake applied cause damage ?

[GTXT23]

Had a question posed to me recently

- If one was to apply the foot brake to a cx~5 awd automatic trans ( say on a hill ) and add power before moving ...about 10 + seconds at low rpm -under 1500k rpm -( which creats a low volume groaning sound ) - would this cause transmission damage ? My answer was no , if for a brief low rpm period as the groaning sound is the torque converter and it is only receiving input power -until the brake is released then the output side moves and then the actual transmission is engagued - anyone have other experience based opinions - Im asking because , she lives near steep hills and does this often- dosent have hill hold - my guess - it can handle much worse - ?? Thnx

 

[Kedis82ZE8]

I wouldn’t do that on mine. Seems like a way to create additional stress and heat on the transmission. I guess low load power braking it would be considered.

I’d ask @sinistriel@ his take on how this affects SkyActiv AT specifically

 

[Conrad 16.5]

10 seconds plus? Why so long?

 

[RedBaron]

If you are revving high enough to create a groaning sound, then you ARE putting excess load on the torque converter. Not good!

 

[Cooter Boy]

What is the point of doing this? She can't go from a dead stop on a hill WITH AN AUTOMATIC?

There is an option called "Hill hold"? In an automatic? Good grief, self-driving cars, here we come because we do not know the basics of driving anymore.

I remember my mother starting on a hill near us all the time WITH A STICK.

 

[Snorting2.5]

If it causes damage, I recommend sticking to the tried and proven method of walking it.

 

[Silly Wabbit]

Brief should be 1 or 2 seconds not 10+. She can also try using the e brake to assist. When you hit the gas hard enough, it should auto release

 

[GTXT23]

Brief should be 1 or 2 seconds not 10+. She can also try using the e brake to assist. When you hit the gas hard enough, it should auto release

Thanks - its a sitiation in which the street is steep and cars are behind her , so rolling back is no good - Ive see people with muscle cars hold the brake and then redline the engine - release the brake pedal and the tires break loose - but that cant be good either - i suspect manufactrers engineer in a tolerance for this - hill hold is a good solution

 

[sinistriel@]

Do not do this, you are generating a significant amount of extra heat inside the transmission by doing this. You are causing the torque converter impeller to fight the turbine assembly. You will cause damage doing this over time.

 

[wlong01]

Easiest thing to do is start the car, make sure the E-brake is on, put it in "D" and press the gas pedal.
The Emergency brake will prevent the car from moving backwards and will automatically disengage.

 

[GTXT23]

Do not do this, you are generating a significant amount of extra heat inside the transmission by doing this. You are causing the torque converter impeller to fight the turbine assembly. You will cause damage doing this over time.

Yes -she said it was one time -and short with brake and gas - so im suggesting the hill hold - appreciate it

 

[GFrosty]

If one was to apply the foot brake to a cx~5 awd automatic trans ( say on a hill ) and add power before moving ...about 10 + seconds at low rpm -under 1500k rpm ...

Nearly 50yrs of driving, here, though I'm nobody's mechanic. I'd equate it roughly with using the clutch to lightly engage a gear as an attempt to hold the hill. Myself, I wouldn't do it with an automatic transmission since I'd assume the wear and tear on the transmission's "gripping" componentry would be impacted similar to how it would be with a manual/clutch system.

On my own 2016.5 CX-5, the normal "hill holder" feature of the automatic transmission works fine on mild slopes, and maintaining my foot on the brake until needing throttle works well (as-designed). Can't imagine how finding an alternative would benefit anything, system-wise. The brake does what it does, well; and the throttle functions properly when needed; with both working as the designers crafted them to work, without attempting a method they hadn't expected me to employ frequently.

 

[cadcamjim]

What is the point of doing this? She can't go from a dead stop on a hill WITH AN AUTOMATIC?

There is an option called "Hill hold"? In an automatic? Good grief, self-driving cars, here we come because we do not know the basics of driving anymore.

I remember my mother starting on a hill near us all the time WITH A STICK.

Ha ha. Same here, my mother was doing that in her late fifties Studebaker with three on the tree.

 

[N7turbo]

Do not do this, you are generating a significant amount of extra heat inside the transmission by doing this. You are causing the torque converter impeller to fight the turbine assembly. You will cause damage doing this over time.

Hmm...was it you who previously said brake torqueing gives the best launches? Granted, we don't do this every day, but it loads the drivetrain and reduces shock so there's less stress to everything except maybe the converter itself due to slippage. And of course the fluid will be warmed up in the process. I just can't see this causing a lot of problems if it's brief, but I'm not a tech.

 

[sinistriel@]

Hmm...was it you who previously said brake torqueing gives the best launches? Granted, we don't do this every day, but it loads the drivetrain and reduces shock so there's less stress to everything except maybe the converter itself due to slippage. And of course the fluid will be warmed up in the process. I just can't see this causing a lot of problems if it's brief, but I'm not a tech.

Brake torque will result in the quickest launches yes but is very hard on the transmission components. When launching with a brake torque method you want to get the rpms up quick and go, not sit there. When you're sitting there holding the brakes like the OP is talking about you have torque multiplication happening at a constant low RPM with low pump and cooler flow against a vehicle that is not moving, this generates a lot of heat. The big concern with doing this is the large pressure building inside the converter which can damage welds on the fins and "balloon" the converter as well as superheating the fluid in a low flow condition. The chances of it breaking anything immediately are slim but making it a habit will cause damage.

 

[Conrad 16.5]

Easiest thing to do is start the car, make sure the E-brake is on, put it in "D" and press the gas pedal.
The Emergency brake will prevent the car from moving backwards and will automatically disengage.

You're suggesting that she shut the car off when she reaches the stop sign at the top of the hill and then restart it with the PARKING brake on?

 

[wlong01]

You're suggesting that she shut the car off when she reaches the stop sign at the top of the hill and then restart it with the PARKING brake on?

Sorry, thought they were talking about from a parked dead stop. I assume OP has a 23 since his handle is GTXT23, doesn't it have the "Auto Hold" function? That would keep the car stationary until gas pedal pressure is applied.

 

[Cooter Boy]

Sorry, thought they were talking about from a parked dead stop. I assume OP has a 23 since his handle is GTXT23, doesn't it have the "Auto Hold" function? That would keep the car stationary until gas pedal pressure is applied.

So will the brake. You can do all this with ONE FOOT.

If someone can't do this WITH AN AUTOMATIC they shouldn't be on the road.

 

[Freedom55]

So will the brake. You can do all this with ONE FOOT.

If someone can't do this WITH AN AUTOMATIC they shouldn't be on the road.

The OP is referring to someone who doesn't have Auto Hold on her vehicle. That person can always mimic Auto Hold by simply holding the brake pedal with the left foot and using the right foot to press the gas pedal while releasing the brake pedal when it's time to take off. It may take a bit of practice to synchronize the procedure in a smooth way but it's not hard to do, I've done it before.

 

[Cooter Boy]

The OP is referring to someone who doesn't have Auto Hold on her vehicle. That person can always mimic Auto Hold by simply holding the brake pedal with the left foot and using the right foot to press the gas pedal while releasing the brake pedal when it's time to take off. It may take a bit of practice to synchronize the procedure in a smooth way but it's not hard to do, I've done it before.

First of all, you should only be using your RIGHT FOOT to operate the throttle AND brake. "Auto Hold" (if I understand what it is) is for people who don't know how to drive.

As I said before, if you can't start from a stop on a hill WITH AN AUTOMATIC then you shouldn't be on the road.

Learn to do it with a stick first, then go to an auto.

I've gotta stay away from this forum.