A question for Techies. - about differences between auto box

[steveperry]

I had noticed on my old '86 190E that if I was on a hill, the car auto box had some mechanism to prevent it rolling backwards. So I could sit there with no feet on the pedals.

However, on my new (or should that be newer ) '98 C240 the car will roll backwards on a steepish hill. So either I have to hold the car on the throttle or more conveniently hold it on the brakes.

Is this a feature that has been lost with the transition from mechanical to electronic gearboxes? Or should I be taking my C240 in for a check?

Also, just out of interest, does the 5 spd auto box circa '98  use the vacuum system at all? I'm sure I can hear the slightest of puff sounds when accelerating hard and the car changes up a gear. Maybe it's just my imagination.

Thanks,

S.

 

[Anonymous]

A question for Techies.

I don't think there is any vacuum usage on the 5 speed box as the electronics can perform all duties.
I suspect the rolling back is due to lack of torque at idle.  My 300TD never rolls back and some times has to be held on the brake to stop forward travel even on steep hills.
It woould be worth checking the car is definately in first gear an the fluid level is right in the box.

 

[Matt Crooke]

A question for Techies.

Steve, i noticed the very same when i first got my 190E. All my previous autos would, when on a hill, roll back in drive, where as my 190 sits stationary, and the slightest blip gets it moving again. This is probably just a difference between the electronic and mechanical boxes. Its really handy in multi storey car parks though!!

 

[fuzzer]

A question for Techies.

Mine does the same

 

[steveperry]

A question for Techies.

"Mine does the same"

Umm sorry to be thick Jason, but does that mean yours does roll back on a steep hill when in drive, or, that it doesn't?



S.

 

[Guy]

A question for Techies.

My C32 and 300TD will both roll backwards on a really steep ramp; (an underground car park) but never noticed it on a road, in either car.

 

[steveperry]

A question for Techies.

Guy,

My old 190E would never roll backwards even on the steepest of inclines, it just locked into position, a light step on the throttle and the car would creep forwards.

My C240 will creep backwards if the incline is steep enough which means keeping a foot on the brakes.

Oh well, I guess it's a feature that's been lost during the transition to newer designs.

S.

 

[Guy]

A question for Techies.

Yeh,
Things change, and not always for the better, but it introduced me to left foot braking!

 

[fuzzer]

A question for Techies.

Sorry , mine rolls back too .

 

[steveperry]

A question for Techies.

Heh thanks Jason no need to be sorry I just read the above both ways so to speak.

I guess I'll stop worrying about mine and get used to the fact I've lost out on a nifty feature from me old car.

S.