"Hill-holder" function (in "C" only)

[DougCLK320]

I found out the other day that the “hill holder” gearbox function - to stop you rolling backwards when stopped on a hill - only works when the gearbox is in “C” (comfort) mode.
When the gearbox is in “S” (sport) mode, if you release the brakes it rolls backwards.
Okay, I can live with this……but why have MB set it up this way?
I can see no reason why, when driving in “sporty” mode, you’d want the facility to have it roll back on a hill.
Strange. Can anyone enlighten me...:?
Doug

 

[ShoeQueen]

Hi Doug

I have no idea but thanks for the heads up .... I also have a 'C' and 'S' mode

 

[DougCLK320]

It's a definite "mechanical" function as, when stopped facing uphill - if the 'box is in "S" it rolls away backward if you release the brake.....stop and press the switch to "C" and you can feel a mechanical lock engage within the gearbox and you can remove you foot off the brake completely and it feels exactly like "park" has been engaged. Hit the gas and drive away....brilliant!!!
Doug

 

[cmax200]

I have had this facility in other makes of autos I have owned and it has not been designed in, it was due to the box engaging 2nd gear (as in C Mode) and this stops it rolling back. I may be wrong but I have always thought as just being a characteristic of Auto boxes.
Now I will stand back and get ready to duck!

 

[television]

The reason is that in the C or W mode, a sprag clutch is used to hold the car from rolling back.

If you want to know what a "sprag clutch" is "google" it and you can read all about it

 

[DougCLK320]

Thanks Malc, but why wouldn't you want it to function in "S"?

 

[television]

Thanks Malc, but why wouldn't you want it to function in "S"?

So that the car can roll back,damaging the rear bumper, in all good for business

This is an individual car thing up to a point, the difference of idle speed of only 25 rpm is enough to let the car roll back or not. Watch the RPM dial when on a hil and see how many revs are needed to hold the car

 

[Alex M Grieve]

Hi Doug

I have no idea but thanks for the heads up .... I also have a 'C' and 'S' mode

But do you not have "continuously variable transmission" (CVT)?

I don't know if these truths apply to your type of gearbox - but they might.

I would test it privately before depending on it.

 

[television]

But do you not have "continuously variable transmission" (CVT)?

I don't know if these truths apply to your type of gearbox - but they might.

I would test it privately before depending on it.

Do any MB's have CVT

 

[Alex M Grieve]

Do any MB's have CVT

From the Transmission tag in optional extras for the B Class (MB UK Website)

Transmission


SE Sport Autotronic - continuously variable automatic transmission with Tipfunction and Speedtronic cruise control □ □ Steering wheel gearshift buttons
Only available for vehicles with Autotronic transmission □ □ Speedtronic cruise control
Only available for vehicles with manual transmission □ □

The table loses its forematting, but the text tells the story.

 

[television]

From the Transmission tag in optional extras for the B Class (MB UK Website)

Transmission


SE Sport Autotronic - continuously variable automatic transmission with Tipfunction and Speedtronic cruise control □ □ Steering wheel gearshift buttons
Only available for vehicles with Autotronic transmission □ □ Speedtronic cruise control
Only available for vehicles with manual transmission □ □

The table loses its forematting, but the text tells the story.

Thank you alex

 

[ShoeQueen]

morning all and HAPPY FRIDAY!
woo hoo off on holiday 2moro ... ..anyway i digress...

I tried tested the 's' thing out this morning and thought I would report my findings, I was stationary at a junction which has a little gradient, there was no one behind me so thought I would give it a go ... took my foot off the brake gingerly waiting for her to roll back .... she didnt!

 

[HJHPH]

morning all and HAPPY FRIDAY!
woo hoo off on holiday 2moro ... ..anyway i digress...

I tried tested the 's' thing out this morning and thought I would report my findings, I was stationary at a junction which has a little gradient, there was no one behind me so thought I would give it a go ... took my foot off the brake gingerly waiting for her to roll back .... she didnt!

Have a great holiday, any where nice? (there's no smilies for jealousy!!)
Anyway on my E Class the hold function works on the S and the C and also works with the gear lever in neutral so I think it may work on the brake/ABS system as opposed the gearbox??
Paul.

 

[ShoeQueen]

jealousy!

thank you i will! im off to the peak district with my boyfriend, he organised it for my birthday hopefully the weather holds... otherwise we will be walking in rain wind snow and ice!:cry:

 

[HJHPH]

Fingers crossed for the weather, we are going there on the 21st for 2 days then the Lake District for the following week. Keeping my fingers crossed for nice weather as I will be driving our winter sun holiday up there!!
Paul.

 

[Micman]

I found out the other day that the “hill holder” gearbox function - to stop you rolling backwards when stopped on a hill - only works when the gearbox is in “C” (comfort) mode.
When the gearbox is in “S” (sport) mode, if you release the brakes it rolls backwards.
Okay, I can live with this……but why have MB set it up this way?
I can see no reason why, when driving in “sporty” mode, you’d want the facility to have it roll back on a hill.
Strange. Can anyone enlighten me...:?
Doug

My car doesn't roll backwards in either C (Comfort) or S (Standard) on the auto box.

It holds it on the biting point and tries to pull forward. I've only known one experience of it rolling backwards and that was on an extremely steep driveway and I had to hold it on the handbrake and give it some revs!

 

[HJHPH]

My car doesn't roll backwards in either C (Comfort) or S (Standard) on the auto box.

It holds it on the biting point and tries to pull forward. I've only known one experience of it rolling backwards and that was on an extremely steep driveway and I had to hold it on the handbrake and give it some revs!

Most autos will hold on the gearbox/tickover facing upwards on a hill, the hold function operates on the brakes and will hold down hill as well. Try that without the hold function
Paul.

 

[television]

The car rolling back in the S mode is only dependent on the idle speed, if set to the highest permissible it will not roll back, if set to the lowest it will may do.

The effect is no different to holding the car by the throttle.

In the W -C mode on the 722.6 box the car cannot roll back, no matter what the idle speed is, as it has a Sprag clutch and it cannot

 

[Dave's E55 AMG]

When "C" mode is selected (comfort) the car pulls away in second gear.
When in "S" mode (standard) the car pulls away in first gear.

If you try the 2 different modes on a steep hill the car will hold when in C mode but will roll back if in S mode - do bear in mind the incline has to be steep in the first place.

 

[JEZ.S320L]

My S-Class 'hill hold' function, works both in W and S mode. Brighton has some quite steep junctions - NEVER rolls back.!