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Discussion Starter · #1 ·
Hi guys, I used to down shift to slow down my previous manual car (especially when down hill) and now, I don't now if it is BAD that I do the same thing to my F30 328i auto transmission? Any thoughts? Thanks!
 

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Brakes are for slowing down the car the transmission is for keeping the engine in the optimum range.

It is not harmful to downshift to slow down but it is not IMO a good practice.

Going down a long hill would be an exception and in that case using engine braking rather than riding the brakes for an extended period is a good idea.

CA
 

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Discussion Starter · #3 ·
Brakes are for slowing down the car the transmission is for keeping the engine in the optimum range.

It is not harmful to downshift to slow down but it is not IMO a good practice.

Going down a long hill would be an exception and in that case using engine braking rather than riding the brakes for an extended period is a good idea.

CA
Even for automatic transmission?
 

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Even for automatic transmission?
High performance driving schools (Skip Barber, Bonderant, etc.) will teach that to slow down you smoothly apply the brakes and modulate them as the car slows down (note that modulating means gradually increasing or decreasing the pressure and is not the same as pumping the brakes). Brakes should be smoothly squeezed, never slammed on even. As the car slows down if you are in manual mode progressively downshift the transmission as the car slows down. In auto mode the steptronic will do this for you.
The car should always be in gear and you should not coast in neutral or with the clutch disengaged (in the case of an MT).
 

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Discussion Starter · #5 ·
High performance driving schools (Skip Barber, Bonderant, etc.) will teach that to slow down you smoothly apply the brakes and modulate them as the car slows down (note that modulating means gradually increasing or decreasing the pressure and is not the same as pumping the brakes). Brakes should be smoothly squeezed, never slammed on even. As the car slows down if you are in manual mode progressively downshift the transmission as the car slows down. In auto mode the steptronic will do this for you.
The car should always be in gear and you should not coast in neutral or with the clutch disengaged (in the case of an MT).
Thank you very much for all the information! But my question is very simple, is it BAD to down shift with automatic transmission (steptronic)? Thanks!
 

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Brakes are for slowing down the car the transmission is for keeping the engine in the optimum range.

It is not harmful to downshift to slow down but it is not IMO a good practice.

Going down a long hill would be an exception and in that case using engine braking rather than riding the brakes for an extended period is a good idea.

CA
I agree with what CA has said here. We live near the bottom of a hill. During our first year of living here, we used to ride the brakes all the way down the hill, and we had to replace brake pads on both cars as a result. Since then, we down shift our vehicles with automatic transmissions to have the engine braking do the job instead of wearing down our brakes.

In suport of CA's explanation of letting the brakes do the job while driving around town, GM essentially recommended, that since today's cars have much better brakes, use the brakes to stop the car instead of manually downshifting. This person also said that it's cheaper to replace brake pads as opposed to a clutch in a manual transmission. The GM rep was referring to a question asked by an owner of a C6 Corvette Z06 with a manual transmission.
 

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Thank you very much for all the information! But my question is very simple, is it BAD to down shift with automatic transmission (steptronic)? Thanks!
It's not bad if you do it once in a while when having some fun. Like everything else, doing it all of the time could potentially develop problems, so why do it often when you have good brakes that can do the job instead
 

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Discussion Starter · #8 ·
It's not bad if you do it once in a while when having some fun. Like everything else, doing it all of the time could potentially develop problems, so why do it often when you have good brakes that can do the job instead
I am just doing it for down hill, so I can make my break life longer. Lol

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Thank you very much for all the information! But my question is very simple, is it BAD to down shift with automatic transmission (steptronic)? Thanks!
If you are asking if it will damage the car or the transmission the answer is no as the steptronic will perfectly rev match the downshifts.

So the answer would be:

Downshifting to slow down the car:

Bad for the car - no
Bad driving technique - yes (unless driving down a long steep hill that would overheat the brakes)

CA
 

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Discussion Starter · #10 ·
If you are asking if it will damage the car or the transmission the answer is no as the steptronic will perfectly rev match the downshifts.

So the answer would be:

Bad for the car - no
Bad driving technique - yes

CA
Ok, I see! But why it's a bad technique?

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I don't know why it's bad technique. I drive on city streets, not racetracks.

I manually downshift my automatic ALL the time because I'm used to driving a manual and that's how I have always driven. To the comment that brakes are cheaper to replace than a transmission, I simply don't get it. I sold my last car with 43k miles and original brakes, so in my mind, I saved at least $1,000 (or more) by not having to replace the pads or rotors.
 

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I have no technical knowledge, but if was bad for the transmission, why would BMW provide so many opportunities for the driver to easily engage in manual shifts?

so the conclusion is it is not bad for the automatic transmission?
 

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I am just doing it for down hill, so I can make my break life longer. Lol

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And that is exactly what you should be doing.

CA
 

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