Auto box downhill "engine braking"

[NorthDownsMerc]

As I live on top of the North Downs, the only way is down so to speak, and that usually mean s-t-e-e-p hills. My latest W220 is doing something different downhill to the last one, and I just wanted some feedback or explanation of what's going on.

The old one (00 S320, 5 speed auto) used to select the highest gear possible and almost freewheel down the steep hills, meaning that a foot on the brake was very much required.

The new one (04 S500, 7 speed) exhibits a much greater engine-braking effect, almost as if it is detected the steepness and has changed itself down to a lower gear. Indeed, if when in "D" you knock it down to a lower gear (using the tiptronic thingy) it will select 2 or 3, rather than 5 or 6 at around 40, indicating to me that it is holding it lower than a freewheel setting. I think it's only doing this after I brake for a corner, and then it's holding the gear rather than changing up and rolling, but I may be wrong.

Am I making sense...? Does this sound normal...? Have Mercedes introduced a hill-descent control logic chip into the system somewhere that I haven't noticed before in any literature...?

Rich

 

[Glenn Smith]

I believe the sensors can detect hill descent, ie no change in speed with your foot off the gas. is it 7speed or 6speed i thought the 7sp was introduced last year

 

[miro]

The last of the W203 cars actually have "active braking". You can feel the brake pedal depress when in speed limiter mode.

 

[portzy]

From memory when reading the initial write up's; the new seven speed 7Gtronic does know when you are going down/up hill. It also knows if you are turning a corner also + it can mix cornering with down/up hill.

Mines exactly like you say.

Portzy.

 

[Satch]

My 5 speed S211 does it, changing down iafter coasting down a steepish hill for a while even without cruise/speed limter on. Appears to try and keep you at roughly the same speed you were going to start with rather than slowing down

Very rarely noticed this in the UK but proved very useful when touring in Germany & Austria.

 

[NorthDownsMerc]

Mines def the 7-speed.

Tried going downhill with cruise control on at 40 the other day - the car rolled up to 50, then changed gear to try and bring the speed down again. Never experienced that before !!

 

[BonzoDog]

My 5 speed S211 does it, changing down iafter coasting down a steepish hill for a while even without cruise/speed limter on. Appears to try and keep you at roughly the same speed you were going to start with rather than slowing down

Very rarely noticed this in the UK but proved very useful when touring in Germany & Austria.

My S211 5 speed will change down going down hill without using CC or limiter.

 

[Birdman]

The W210 E55 has the W140 S600 5-speed box. According to the owner's manual the box will change down once when cruise control is on, in order to regulate speed downhill, and this is my experience.