NickCats

Ok, I know that the manual C300's have a feature called Hill Start Assist that helps prevent rolling back on an incline. Does anyone know if this is something that is also included with an automatic transmission ? It seems like my C350 has this, but I can't tell if it's the brakes or just the simple fact that the car is in drive that keeps it from rolling back on a hill.

Thoughts ?

Nick

C300Sport

Yep, we all have it...just more noticeable on the manuals.

Egonvdv

yes it does

I_Love_MB

Put it on ''N'' and see what happens ! By the way we do have this feature for auto.

AMGTTV8

Hate to be the party pooper but when I put my car in neutral on any sort of a hill it rolls.

NickCats

Thanks, everyone, that's what I thought but I couldn't find anything on the Mercedes website to confirm one way or the other.

Here's what it says at mbusa in the performance section regarding the advanced braking systems :

The 4-wheel disc brakes in the C-Class offer our electronic 4-channel Antilock Braking System (ABS), an industry landmark pioneered by Mercedes-Benz in 1978. Take comfort in powerfully precise, nearly fade-free stopping control courtesy of large brake-disc dimensions - 11.6" up front on C300 Sedans and 12.7" on C350 models, and 11.8" in back - and aluminum front brake calipers.(1) The systems are also enhanced with still more innovations, from Brake Drying that ensures maximum stopping power in inclement weather to Hill-Start Assist that helps prevent rolling back on an incline.

C300Sport

It only works when the car is in gear. If you have it in neutral, the car "assumes" you want it to roll.

If you are in a forward gear on an uphill grade with the brakes on, hill assist will activate

If you are on a downhill grade in reverse with the brakes on, hill assist will activate

I_Love_MB

Never tried it myself .. but what C300Sport said make sense.. Anyway..I'm pretty sure we do have it for Auto.

Carsy

I am almost sure this is not a feature in automatics. Why would it be ?

jstaneff

One option would be to "feather" the gas to keep the transmission "pulling" when stopped on a hill. That's apparently bad for the transmission.

Another is one foot on the gas and one foot on the brake. Works, but there's that two-foot clutter going on, and with the auto, the wrong foot is on the brake.

My C300 7-speed is equipped with hill start assist. Very useful in Seattle. Evidently there's a smallish brake on the drive shaft that does this?

The delay is supposed to be 2 seconds, but I've seen up to 10 seconds. Very nice to take the foot off the brake and the car just sits there until you press the gas.

NickCats

jstaneff,

Thanks for the feedback. I was hoping someone from somewhere with more drastic elevation changes than what we have here in Illinois would confirm that our cars with an automatic transmission have hill start assist.

Nick

C300Sport

Check out page 246 of the owners manual PDF....automatics do indeed have hill assist.

RLE

...

Carsy

The 220 CDI diesel automatic ( 5 Speed) has sufficient torque at idle speed to power the car UP steepish slopes in' drive' just like a tractor.The Hill Start Assist does not seem to come into play. The foot brake has to be used to prevent you going FORWARD !!

jstaneff

Importantly you should recognize that while we all have the same make and model, each car is an individual. The hill I speak of drops 150 ft in 4 blocks, not a gentle slope by any means. It's the end of my daily commute, and the car works as I have described. Your car may vary, maybe I got a great one!

As to holding the car with idling and using the auto trans to keep it in place, I was always taught that to be a bad idea. Something about how the tranny works (internal clutches). Your experience may differ, and I'd admit that most of the folk who taught me thought automatics were really new-fangled things. I still have one car with a clutch and manual transmission, and never use that to hold it at all, ever.

In fact, looking it up on the web this morning gave this result:
"automatic transmission is not designed to hold a vehicle on a hill - it will just overheat and eventually need major repair. Some vehicles have a "hill holding" option that locks the brakes, but it doesn't use transmission"
Which sort of says the same thing, eh?

Merry Christmas!

myinternetsucks

As preference for me, when I see someone driving with one foot on the brake and one on the gas, I ask to get out or drive. Seriously, that is one of my biggest pet-peeves EVER!

Carsy

This morning I stopped on a 1 in 4 slope hill . I am now a believer !! Gravity overcame the diesels torque & the 'Hill Start Assist' held the car for a couple of seconds as it should. If felt & sounded as if it were the brakes that was doing the work.

Thanks to this forum I continue to learn snippits about my vehicle. eg I was under the impression that my 220CDI had a particulate filter but this is not the case for Australian vehicles of 2008 complience. I have 2 canisters in the exhaust line but both are catalytic convertors. Particulate filters have differential pressure sensors fitted.