Auto transmission jerking?

[WaFu]

My 135 with steptronic is jerking.. (It feels like going from 2nd to 1st gear) when I am on brake to a slow stop (Not always, just 1 out of 5 to 6...). Anyone experience that? I tried to the shift program by holding the accelerator more than 10s. It help at the beginning, but the jerking keep coming back after I drive it awhile. I really drive me nuts.

[shawshank772]

This is only my short experience from test driving it, but also with a Benz AMG c32. It always wanted to stay in that higher RPM range so when you would let off the gas it felt like it would bog into that lower gear and jerk. I know the harder I drove the car the more it would do that. It kept thinking I wanted to be in the "power band" so it would stay there and jerk down. I am no automechanic or race car driver (obviously) so take what I say with a grain of salt

[WaFu]

This is exactly what I think too. If I do a hard stop it won't be a problem at all.. since the computer will know I want to stop and then no gear changing.
However most of my daily driving is on city road, not track... so I just want a smooth stop and then I step on the brake half way until it stop, but in the mean time it just down shift. If the brake isn't that hard to modulate then it won't be a problem. I hope it will be smoother after I break-in the brakes.

[Kiety]

could be the soft stop feature? try not letting up on the brakes wen you almost come to a stop. there's a couple threads on this, try a search

[Rotorhead]

I noticed this when I test drove the auto(that's all they had to drive) and it was really annoying. I ordered a six speed so I don't think it will be a problem there, but I feel your pain for you auto guys.

[WaFu]

Sounds like it is the Soft stop.. So I shouldn't let off the brake like other car.. (What a new things to learn...)

Originally Posted by Kiety

could be the soft stop feature? try not letting up on the brakes wen you almost come to a stop. there's a couple threads on this, try a search

[alivebacon]

I don't get this problem at all

[WaFu]

I think it really depends on how you press on the brake.
For some driver who used to release brake after (or almost) to a full stop, then they will notice about that.
For some driver who used to step on the brake until complete stop then they won't notice the problem.

[Uptown Bully]

Wait, what? Why would you let off the brake at a stop? You slow down, you stop, you hold the brake until it's time to go. Isn't that how it's supposed to be done? Or is the OP stopping then sort of slowly creeping fwd?

[hellrotm]

Oh boy,

I hope this isn't the famous "auto transmission slam". Car jerks forward when stopping. As problem gets worse it can even feel like you have been rear ended. BMW had a service bulletin to fix it on 5-series and the 7-series

[painter]

When braking at a stoplight, I am beginning to notice this problem with the steptronic also - seems like a hard jerk slightly forward into 1st gear - both in drive and sport.

Any thoughts?

:iono:

[mistermojorizin]

i had to drive an auto for a day, a 328 and it was a pain in the arse. but i figured out that its better in ds when going slow, and better in d when going fast. so as i slowed down I would just switch it over to ds before stopping and it seemed to do the trick.

i saw a discussion about this problem on e90post too. i forget the resolution but it had a very good description of the problem and exactly what causes it.

[WaFu]

Yes, that's true. I never exp. a jerk when in DS mode.. I think usually DS mode will start with 2nd gear.. so I never goes to 1st at stop.
It is the same if you push the paddle anytime before you stop, then you will not have the jerk, since it won't go lower than M2.
Anyway, I stop by dealer today and have them look at it.. I don't know what they've done on it, but I didn't notice any jerk when I was on my way home. I hope it solve the problem.

Originally Posted by mistermojorizin

i had to drive an auto for a day, a 328 and it was a pain in the arse. but i figured out that its better in ds when going slow, and better in d when going fast. so as i slowed down I would just switch it over to ds before stopping and it seemed to do the trick.

i saw a discussion about this problem on e90post too. i forget the resolution but it had a very good description of the problem and exactly what causes it.

[WaFu]

Just a follow up with yesterday's service..
Drove it all day today, and don't see any jerk at all. I think they fixed the problem

[ChrisK]

Did the dealer note what they fixed on your paperwork?

[WaFu]

No.. nothing there, but the jerking is long gone.

[ChrisK]

Well at least they fixed it. :w00t:

[shawshank772]

I was reading on e90 post and they do have some ecu flash that helps out with this jerking. They probably installed that I am assuming

[painter]

I am continuing to experience this problem with my 135i steptronic (hard gear change from 2 to 1, slight surge forward when soft braking at a stoplight) - only after the car warms up. It doesn't happen until it reaches full operating temp.

I'm going to stop by the dealer for a chat. I'll mention your "flash" idea, although I have no idea what that means.

:iono:

[WaFu]

Flash - similar to your software update in your computer.

[painter]

Originally Posted by WaFu

Flash - similar to your software update in your computer.

Thanks - I feel a little smarter now.

[benc008]

slickone -

I hope this isn't the famous "auto transmission slam". Car jerks forward when stopping. As problem gets worse it can even feel like you have been rear ended. BMW had a service bulletin to fix it on 5-series and the 7-series

shawshank772 -

I was reading on e90 post and they do have some ecu flash that helps out with this jerking.

slickone - can you tell me more about this "auto transmission slam" service bulletin? I had the same problem and got a software update from the BMW dealership but the problem remains. Help!