Can rolling back in drive damage the car?

[Jazz2021]

My wife is new to automatics, so it's been interesting watching her drive our new Jazz hybrid.

Our drive is on a slope down from the road and is L-shaped. Previously, with our old manual Honda HR-V, we would turn on to the drive and then perform a three-point turn on the drive so that the car could exit the drive going forwards when we next used it.

The last part of the manoeuvre with the manual car was to roll back a bit downhill with the foot on the clutch but the car still in first gear. I told my wife this is not possible on an automatic because you have to put it in R then D to complete the move. But she told me she did it perfectly well by staying in D and just taking her foot off the accelerator. And it does work.

So my question is, are we damaging the transmission (or anything else) by doing this?

[sportse]

Probably not, although it will be putting a small increased strain on the electric motor as it has to stop the backwards movement before going forwards.

I have a hill near me with traffic lights, the slope varies so if you stop on some parts the hill start assist means the car doesn't roll back but on another part the car does roll back slightly.

I try to remember to put on the brake hold beforehand if I'm stopped on that part.

[guest9814]

In manual mentioned that holding car fromm rolling back on road in D with pressed gas pedal can damge motor, so this backward move  in D also can be dangerus for electric motor i think.

[guest10621]

I remember hearing a long time ago that when an electric motor is running it generates a smaller electrical current of the reverse polarity to the supplied current, which is sometimes referred to as a "back-emf" (where emf = electromotive force). This effectively reduces the current flowing through the motor's coils. To save money and weight, some manufacturers design their electric motors so that they can handle the reduced current, but would overheat and become damaged if exposed to the full supplied current.

If the electric motor is prevented from rotating, for example being held on the throttle when the vehicle is facing uphill, there would be no back-emf and thus the full applied current would be flowing through the coils with the possibility of causing damage.

In the case where current is applied to the motor but the vehicle was rolling backwards, presumably the generated current would be the same polarity as the applied current and thus be more likely to cause damage.

Whether Honda use motors that can survive these currents, or if the electrical controlling system has safeguards to protect the motor in these scenarios, I don't know, but it would probably be best to avoid them.

[Bristol_Crosstar]

My wife is new to automatics, so it's been interesting watching her drive our new Jazz hybrid.

Our drive is on a slope down from the road and is L-shaped. Previously, with our old manual Honda HR-V, we would turn on to the drive and then perform a three-point turn on the drive so that the car could exit the drive going forwards when we next used it.

The last part of the manoeuvre with the manual car was to roll back a bit downhill with the foot on the clutch but the car still in first gear. I told my wife this is not possible on an automatic because you have to put it in R then D to complete the move. But she told me she did it perfectly well by staying in D and just taking her foot off the accelerator. And it does work.

So my question is, are we damaging the transmission (or anything else) by doing this?

I think you just need to select N ('Neutral') then the car will roll if it's on a slope and shouldn't do any damage, I've done this when pulling up to a road junction on a hill and I've gone a bit too far forward

[Neil Ives]

I think you just need to select N ('Neutral') then the car will roll if it's on a slope and shouldn't do any damage, I've done this when pulling up to a road junction on a hill and I've gone a bit too far forward

Yes, in neutral, foot on brake so the handbrake can be manually  released, ease pressure on brake pedal to allow the car to roll. That should work I think.

[nowster]

I think you just need to select N ('Neutral') then the car will roll if it's on a slope and shouldn't do any damage, I've done this when pulling up to a road junction on a hill and I've gone a bit too far forward

Yes, in neutral, foot on brake so the handbrake can be manually  released, ease pressure on brake pedal to allow the car to roll. That should work I think.

You'll also need to turn off "Brake Hold" to roll back in Neutral.

[Zaier]

If it's not done for a long time, it won't damage anything.
When you're doing it, you're creating some current in the motor coils with opposite "direction" than the one which the inverter is trying to create, and thus heating up the coils, but at such low speed the power and thus the heat generated should be very very low.
Anyway, if you want to avoid this, just switch to N or R and then put back to D.

[Jeff15]

Use brake hold...