siren001

Hi,

I'm not sure if this is just me or a common thing. But driving in comfort mode, once I come to a complete stop the car doesn't go to 1st, It only goes as low as 2nd gear. I am bringing it into the shop next week for A1 service so I wanted to make sure this is common behavior or abnormal.


Thank you!

mrmotoguzzi00

It's normal you won't get 1st gear unless you go to manual mode or sport mode.

Sigp232

C or E starting on 2nd gear is normal.

siren001

That's good to know, its a bit rough when you are in hilly neighborhoods.

Sigp232

Put in sport mode on hills or turns will be/stay in 1st

siren001

Yah I've been doing that but wanted to make sure, since I'm taking it in for its 1st service.

decorily

My 250d always goes to 1st in any mode!

openwheelracing

1st gear is rarely used in a 9 speed auto

decorily

Well in my 9 speed auto it's used every time I start the car and every time I come to a stop!!
Nothing rare about that!!

Gnidolfo

Probably because the engine is smaller and doesn't feel comfortable to start the car from 2nd gear, my gle43 never goes to 1st gear in C mode

decorily

I don't think the engine size is the issue...the torque in my 300d isn't very much different to the GLE 43 and then take weight into consideration.

W205C43PFL

Back in the GLK days, 2nd gear results in rollback when on an incline, the GLC has hill start assist (iirc), but main reason to start in 2nd gear is to save fuel which allows the vehicle to get to the most efficient gear as soon as possible (in this case the 9th gear), which is probably why it has 9G to begin with, more gears, more fuel efficient in this case.

superswiss

Many automatic transmissions start in 2nd gear for normal driving. 1st gear is often very short and not needed to just drive off on level grounds. It's done for comfort mostly. In case of a torque converter, the torque converter itself acts as a gear, because of its torque multiplication that occurs while the input and output rotate at different speeds, so in effect you are starting in a lower gear and then gradually change into the actual 2nd gear. It's actually a bit like a CVT off the line as the torque multiplication gradually reduces as the output shaft catches up to the input shaft.

The 9G has a very short first gear. The main benefit of having more gears is that the lower gears can be kept short for acceleration while still having taller gears available for fuel efficiency once cruising. The ratio spread is huge on the 9G. The first 6 gears are your normal driving gears, with 6th gear being direct drive, but then it still has 3 overdrive gears for fuel efficiency. Most regular MB models drive off in 2nd gear while in Comfort. Newer AMGs with the 9-TCT and 9-MCT always drive off in 1st gear for a better response.

But to start in 2nd gear the engine needs to make enough torque. To the person above with the 250d, it's not the peak torque that matters, it's the torque off the line, which is quite low in a 250d. To make the peak torque your engine needs boost from the turbo. W/o boost all you have is a small displacement. Small displacement diesel engines are dogs below boost rpm and need a lower gear ratio to start off. You need to compare the torque curves, because ICE don't make instant torque like electric motors.

decorily

If torque "off the line " is so low why are diesel engines favoured for towing?

superswiss

Always comes down to gearing and displacement. Why do you think semi-trucks have up to 18 gears?

decorily

I understand gearing....not sure what your point about needing turbos is!

superswiss

There are two ways for an engine to make torque. Displacement or forced induction. The displacement in an engine is fixed, so to make more torque than the displacement naturally makes you need forced induction. That's where the turbos come in, but the turbos need to spin up first to help make more torque, hence why below a certain rpm you don't get any forced induction. In case of the 250d I believe boost comes in at 1600 rpm, so to make full torque the engine has to spin at 1600 rpm at least. Below that you get much less torque. Having short gears allows the engine rpm to be high enough for the turbos to produce boost.

Willie G

I think most people don't realize how crucial forced induction is to an engine that is designed for it. I certainly didn't until the supercharger belt broke on my SL55. That thing turned into a turtle and in all seriousness, my base model Kia Soul daily driver at the time was noticeably sportier than the SL55 without a supercharger, my mind was blown!

dadalook

This was the exact same question I asked my service adviser when i took the car for service..

Once the engine runs in and adpot to your driving, it will eventually always start at 2nd gear from a traffic stop unless you put it in park gear. The 2023 A250 loaner that I got with only 1K starts at 1st gear from traffic stop and it is very slow and tough start every time.

eddieo45

This is literally the definition of Comfort Mode: "Comfort is the default setting when the vehicle is first turned on. Starting in 2nd gear, it provides earlier, smoother shifting for comfortable and refined cruising. This mode engages the ECO-Start/Stop system for the best fuel efficiency." I've become so used to it that starting in 1st gear feels weird. My ML400, my most recent acquisition, is my first Benz without Dynamic Select.
Actually, it's easily overridden by throttle action: give it enough gas and it starts in first.

TouringFordor

Yes, it's normal. Nothing really new; some automatic transmissions have started in second since the late 1940s.

schroedinger

Can you downshift to first using the paddles?

W205C43PFL

Normal, it is a way to save fuel, but your vehicle might rollback when on a hill because of that, it was a common issue for GLK SUVs but has been solved with MB's Hillstart Assist (might have remembered the name wrong)

W205C43PFL

Certainly or alternatively if you hate it sport mode will make sure to downshift to 1st gear when stopped.