Automatic rolling back on steep incline!

[syedeali]

I don’t know if this is expected behaviour as this is my first automatic so maybe a noob question. When i get to a steep hill and bring the car to a stop by braking it stays still for a moment as i release my brake, it then starts rolling back down!!

However on a slight incline it stays stationary or slightly edges forward as id expect.

 

[wireman]

On a steep hill it would be fair to expect this behaviour, on lesser gradients you can expect the creep torque to hold you. Your owners manual should provide some guidance.

Use left foot braking to hold the car as you set off, or revise your use of the parking brake and stop it from rolling with that, just like the driving test in a manual transmission car expects and you should have been continuing to do since you passed it.

There is much debate in advanced driving circles about the need to use left foot braking in modern automatics, none of it very conclusive, some of it a dogmatic no.

My ageing 124 will hold a 1:7 on creep but it feels very insecure, the PB holds a 1:3, just.

 

[whitenemesis]

Some advise putting the 'box into W (or E for newer models) mode for additional hold on slopes.

 

[whitenemesis]

The owner's handbook details "Hill Start Assist" whereby the brake remains engaged for approx 1sec after release.

Does your car have this?

 

[television]

In the C or W setting on the box a sprag clutch is employed so that the car cannot roll back on a hill

 

[whitenemesis]

In the C or W setting on the box a sprag clutch is employed so that the car cannot roll back on a hill

Is that C and W or only W ?

 

[syedeali]

The owner's handbook details "Hill Start Assist" whereby the brake remains engaged for approx 1sec after release.

Does your car have this?

Yes it does,

 

[syedeali]

Is that C and W or only W ?

i dont have a W setting, i have c, s, and m. i dirve normally on C

 

[syedeali]

Ive done some googling and have found that it all depends on the car/model some cars seem to roll back other stay still regardless of what incline they are on.

Im not overly bothered just wanted to know if this was expected behaviour?

 

[television]

Is that C and W or only W ?

The wording changes over the models C is comfort equivalent to W on other models, in S the car can roll back, it is the second gear start mode where this is fitted

 

[whitenemesis]

Ive done some googling and have found that it all depends on the car/model some cars seem to roll back other stay still regardless of what incline they are on.

Im not overly bothered just wanted to know if this was expected behaviour?

Yes it is expected behaviour

 

[alexmoon]

On my E Class I have S and W settings. Was told they stand for Summer and Winter. W starts in a higher gear so as not to bring on wheel spin in ice or snow – hence W for winter. Don't know if this is true – though it seems to make sense. As for rolling back on hills, if it does roll then hold car on foot brake, then accelerate when ready to go.

 

[syedeali]

Yes it is expected behaviour

Thats all i needed to know, not having driven an automatic before i wasnt sure about this. Thanks

 

[moosehead]

I would imagine then this has a 7G box if it's a 320 W204? My 7G rolls back or forwards on any incline regardless of whether it's in 'C', 'S' or reverse whereas the 5 speed on the wifes SLK seems to hold on pretty much any incline.

The hill starts are not too much of a problem once you have mastered left foot on the barke pedal or the parking brake. Parking on an incline is a real pain. I've mentioned this to the dealer a number of times and it seems to be a 'feature' of the 7G.

 

[television]

I am sure that the 7g has a sprag clutch to prevent this just like the 722.6 box that comes in in the C or W mode, a slight increase in the RPM will hold the car, but that is a catch22 now, for if on the petrol engines you have your foot on the brake, the engine will cut and not rev