theraj2

This has happened on several occations:
Last night for instance, I was making a u-turn and some of the streets in ny arent completely level. I put to car in reverse to complete the turn, and the car began rolling foreward into the sidewalk(dint hit it) Then a few times when im coming up my driveway the car began rolling backwards if i dint press hard enough on the gas.

Is this normal? or should i take it to get checked out?

tmehanna

Is this a brake or a transmission question? You find it strange the car rolls on inclines if you don't use the gas pedal? What do you want it to do? Hill Assist braking disengages in 2-3 seconds after you release the brake pedal and then car starts to roll unless you use the gas pedal.

theraj2

^ it happens very sudden, the second you let go of the brake, the car begins to roll... This isnt a normal thing for cars, my friends IS 250AWD doesnt do this, the lexus i own now doesnt do this ither. I've never tested it on my c300, but if im at a stop light on a hill, and i let go of the brake, the car will roll down? .. I have tested it with the IS, and my GX the car doesnt roll, but it just sits there until your ready to go, and especially when your in the IS, it senses that your on a hill, so the slightest tap on the gas runs the rpm enough to move the vehicle easily up the hill.

dont get me wrong... I love my C300, just want to know why this happens.

jmoney6

I would get that checked out, my moms 203 c280 doesn;t roll back on hills.

tmehanna

If the car starts rolling as soon as you release the brakes on an incline, you should have it checked. Sounds like Hill Brake Assist doesn't work on yours.

kimyoung_k

I am wondering which mode your transmission was set at "C" or "S".
In "C" mode, both forward and reverse gear always starts at 2nd which might be the reason why the car could roll down on hill easily when release of brake pedal. still you would have Hill Assist Brake system that hold the brake for 2-3 seconds after release of brake to prevent the roll.

Try with "S" mode to see if your car would still roll at the hill where your other car would not.

AsianML

I recall reading on these forums that the inverse happens in regard to transmission mode. C would hold the cars in inclines, but S would let it roll.

But there sounds like there is a problem with theraj2's C since Hill Start Assist should hold the brakes for several seconds before it releases them.

theraj2

I keep it in c mode all the time(for gas and comfort reasons) still rolls

kimyoung_k

In C mode, mine rolls back on my sloped driveway after Hill Assist brake times out in 2-3 sec. I have not tested with S mode yet though.

As long as your Hill Assist braking works, I think it is normal.
It maybe the characteristic of our 7sp-Auto transmission. That's why MB added Hill Assist braking for us

My old 96 C220 did not roll back at all, actually it climbed up if the hill was not that high.