Comfort Mode Doesn't Shift to 1st Gear at stop
#1
Comfort Mode Doesn't Shift to 1st Gear at stop
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!
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!
#2
MBWorld Fanatic!
Join Date: Aug 2005
Location: Sarasota, Florida
Posts: 1,300
Received 195 Likes
on
168 Posts
16 E550 Cab, 2003 Ram bright red crewcab 4x4 we call Clifford :)
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!
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!
It's normal
![Smilie](https://mbworld.org/forums/images/smilies/smile.gif)
#5
Senior Member
Trending Topics
#9
MBWorld Fanatic!
#10
Newbie
Join Date: Oct 2022
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
2017 Mercedes-Benz AMG GLE43
#11
MBWorld Fanatic!
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.
#12
Out Of Control!!
Join Date: Dec 2019
Location: Yours to Discover
Posts: 13,859
Received 2,643 Likes
on
2,247 Posts
PFL205.064 with M276.823 (Oil pump solenoid defeated)
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.
#13
MBWorld Fanatic!
Join Date: Nov 2018
Location: San Francisco Bay Area
Posts: 8,581
Received 3,921 Likes
on
2,622 Posts
2019 C63CS
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.
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.
Last edited by superswiss; 10-07-2022 at 02:13 PM.
The following users liked this post:
ajmtbm (10-08-2022)
#15
MBWorld Fanatic!
Join Date: Nov 2018
Location: San Francisco Bay Area
Posts: 8,581
Received 3,921 Likes
on
2,622 Posts
2019 C63CS
#17
MBWorld Fanatic!
Join Date: Nov 2018
Location: San Francisco Bay Area
Posts: 8,581
Received 3,921 Likes
on
2,622 Posts
2019 C63CS
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.
#18
Newbie
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.
#19
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.
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.
#20
MBWorld Fanatic!
Join Date: Feb 2004
Location: Milton, MA USA
Posts: 2,977
Received 179 Likes
on
149 Posts
me: 2015 SL400 & 2015 ML400; wife: 2022 GLC Coupe kid: 2017 GLC SUV
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.
Actually, it's easily overridden by throttle action: give it enough gas and it starts in first.
Last edited by eddieo45; 02-23-2023 at 07:04 AM.
#21
Newbie
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!
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!
#23
Out Of Control!!
Join Date: Dec 2019
Location: Yours to Discover
Posts: 13,859
Received 2,643 Likes
on
2,247 Posts
PFL205.064 with M276.823 (Oil pump solenoid defeated)
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!
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!
#24
Out Of Control!!
Join Date: Dec 2019
Location: Yours to Discover
Posts: 13,859
Received 2,643 Likes
on
2,247 Posts
PFL205.064 with M276.823 (Oil pump solenoid defeated)
The following users liked this post:
mikapen (03-11-2023)