[fongph]

Hi,

I wonder if anybody has experienced the "slam" or "bang" symptom when acclerating from a stop or decelerating and accelerating again. I don't know if it is a GM transmission thing; I have done some research on this issue and it turned out it is infamous for E60 and some 7 series. I can't seem to fine anything in particular to E9x though. my car is a 08 and it only has 4000 miles on it. I have experienced 5-6 times out of 20 times that I tried to accelerate rapidly. I think it got worse depends on how quick I want to accelerate. You will feel that some part of your drivetrain, mostly from transmission is hitting a "wall" so a slam / bang should best describe it. It is not metallic sound. For your information, all occurence of Slams/ Bangs were all when I was driving in "D" mode. The loudest slam I have had is when I try to make a quick left turn to beat the oncoming traffic so I floored it and "BANG" that I almost think I hit something. Correct me if I can wrong, I think in "D" mode the gear stays in 2nd and the attempt to accelerate rapidly requires a downshift into 1st and the transmission slam is indeed a 2->1 downshift harshness problem during the kick down process, right? I didn't have that problem in my E46 325i as I can remember. Please chime in for all 6AT Steptronic E90 owners. Thanks

[Dragonman4]

If it's only got 4k miles on it, take it to the dealer for warranty repair. Definitely doesn't sound normal.

[blue2fire]

Not normal, take it to the dealer.

[methodtim]

To the dealer you go!

[edb5020]

Take it to the dealer, but trust me, they will tell you it's normal. I Promise.

I had the same problem with an 08' 328xi. I was back and forth from the dealer 6 times in the 5 months I had the car. The transmission software blows BIG TIME, and you can have all the updates and transmission resets in the world and it won't fix the issue.

I ended up doing a trade assist after contacting BMW NA. After a field engineer came in to give the approval, I was given another brand new 328 this past June. This one works better but is still not perfect.

If you are not having any other issues (which I WAS having many other issues besides the one you are describing) then I would not bank on the dealer doing anything about it....I'm not trying to discourage you, but I am just being honest from what happened at my dealer - I feel all dealers are this way (maybe I'm wrong).

But all in all, best of luck to you with figuring out the issue. Definitley keep us updated and make sure YOU STAY ON THE DEALERS ASS about it!

[Christos]

Originally Posted by fongph

Hi,

I wonder if anybody has experienced the "slam" or "bang" symptom when acclerating from a stop or decelerating and accelerating again. I don't know if it is a GM transmission thing; I have done some research on this issue and it turned out it is infamous for E60 and some 7 series. I can't seem to fine anything in particular to E9x though. my car is a 08 and it only has 4000 miles on it. I have experienced 5-6 times out of 20 times that I tried to accelerate rapidly. I think it got worse depends on how quick I want to accelerate. You will feel that some part of your drivetrain, mostly from transmission is hitting a "wall" so a slam / bang should best describe it. It is not metallic sound. For your information, all occurence of Slams/ Bangs were all when I was driving in "D" mode. The loudest slam I have had is when I try to make a quick left turn to beat the oncoming traffic so I floored it and "BANG" that I almost think I hit something. Correct me if I can wrong, I think in "D" mode the gear stays in 2nd and the attempt to accelerate rapidly requires a downshift into 1st and the transmission slam is indeed a 2->1 downshift harshness problem during the kick down process, right? I didn't have that problem in my E46 325i as I can remember. Please chime in for all 6AT Steptronic E90 owners. Thanks

I hate to tell you, but its very normal. That's why I got rid of my 328xi You'll find many of my original posts on this issue at Bimmerforums. I know of another forum member who got a trade assist out of the car and into a 335i because of these same reasons

Here is an editorial response from Roundel magazine January 2009 issue, page 105, on the 328 tranny.

" You have described normal vehicle function with the GM 6 automatic transmission, which is, without question, the worst-performing BMW automatic transmission I have ever tested , dragging the "automatics suck" paradigm to new depths of misery. The solution would have been to order the car with the preferred manual gearbox."


One other point it's mostly the xi version of the 328 AT's that basically suck. The "i" versions are not perfect but seem better and the 335i's are wonderful, hate to rub it in.....