A-Trans lurches from standing start

[thekozer]

I've read many posts about something similar, but everyone attributes this to starting off in 2nd gear. All I know is this, I have an 08 135i convertible that accelerated flawlessly (regardless of mode or gear) for 28 mos. Now when I am stopped at a traffic light and then accelerate (even mild acceleration) there's a hesitation and the the car lurches forward somewhat violently. It's almost as if the car had slipped into nuetral while stopped then jumps into gear. Has anyone had a similar experience and was there a resolution?

[amancuso]

Originally Posted by maxnix

A "feature" of the "lifetime fill"?

If there is a dipstick for the Steptronic, you could do the white paper towel test. Any difference in color between your ATF color and the color of new ATF is indicative of fluid degradation.

The Automatic Transmission no longer has a "lifetime fill." The warranty booklet states that it should be changed @ 100,000 miles. Personally I will be changing mine every 60,000 miles just as I have on my other BMWs.

[tylerh269]

Originally Posted by thekozer

I've read many posts about something similar, but everyone attributes this to starting off in 2nd gear. All I know is this, I have an 08 135i convertible that accelerated flawlessly (regardless of mode or gear) for 28 mos. Now when I am stopped at a traffic light and then accelerate (even mild acceleration) there's a hesitation and the the car lurches forward somewhat violently. It's almost as if the car had slipped into nuetral while stopped then jumps into gear. Has anyone had a similar experience and was there a resolution?

Same thing is happening to mine i took it to my dealer multiple times and the last time they took it they did some type of readjustment to it and is still doing it but now the cold weather has passed and is has not been doing it since idk if it was possibly due to that or what, but that is a real potential of being dangerous.

[amancuso]

Originally Posted by maxnix

I would recommend a mechanical exchange (not just a drain and refill which only dilutes the old fluid with the new) every 30K if you are keeping your car to 100K.

Is there an a ATF cooler on these Steptronic cars? I don't mean an in radiator heat exchanger either which serves a different purpose.

Thanks for that bit o'advice. I might consider it, but to be honest, I have followed the above mentioned schedule for the past 10 yrs on every auto bimmer I have owned, and I've never had an issue. I really think the failures are overblown. I seem to read about more HPFP failures then auto trans. failures on forums. Just care for your car, and respect it. It in return will take care of you.

This might be of some help to the OP. Not sure how true this is, but my 128i is an N51 engine'd car. I was told that when the car is cold, ie. starting after sitting over night, that it will shift itself into neutral at stop lights until normal operating temp is achieved. I have noticed that there is a little hesitation when starting from a stop almost as if the car is indeed shifting from N to D. When the car is warmed up this symptom is completely gone.

To me, it's just a minor irritant and not really a big deal. I don't know if 135iA's are programmed the same way, but this could be the same thing.

Al.

[tylerh269]

Originally Posted by amancuso

Thanks for that bit o'advice. I might consider it, but to be honest, I have followed the above mentioned schedule for the past 10 yrs on every auto bimmer I have owned, and I've never had an issue. I really think the failures are overblown. I seem to read about more HPFP failures then auto trans. failures on forums. Just care for your car, and respect it. It in return will take care of you.

This might be of some help to the OP. Not sure how true this is, but my 128i is an N51 engine'd car. I was told that when the car is cold, ie. starting after sitting over night, that it will shift itself into neutral at stop lights until normal operating temp is achieved. I have noticed that there is a little hesitation when starting from a stop almost as if the car is indeed shifting from N to D. When the car is warmed up this symptom is completely gone.

To me, it's just a minor irritant and not really a big deal. I don't know if 135iA's are programmed the same way, but this could be the same thing.

Al.

I believe that is the case due to my car has not hesitated since it has warmed up where i am at.

[DriveHard]

Originally Posted by amancuso

Thanks for that bit o'advice. I might consider it, but to be honest, I have followed the above mentioned schedule for the past 10 yrs on every auto bimmer I have owned, and I've never had an issue. I really think the failures are overblown. I seem to read about more HPFP failures then auto trans. failures on forums. Just care for your car, and respect it. It in return will take care of you.

This might be of some help to the OP. Not sure how true this is, but my 128i is an N51 engine'd car. I was told that when the car is cold, ie. starting after sitting over night, that it will shift itself into neutral at stop lights until normal operating temp is achieved. I have noticed that there is a little hesitation when starting from a stop almost as if the car is indeed shifting from N to D. When the car is warmed up this symptom is completely gone.

To me, it's just a minor irritant and not really a big deal. I don't know if 135iA's are programmed the same way, but this could be the same thing.

Al.

+1 HERE... And you can prove itto yourself.

I know what I am about to type may sound wierd, but do it once and you will see.

Being that it is cold related..

on a similar cold morning, go out and start your car, put it in gear, set e-brake... let idle for 5 minutes or so... less than 10 then go for your regular ride. you will see that you no longer have the warm up delay that is built into the trans.

PLEASE BE CAREFUL LEAVING A CAR IN GEAR UNATTENDED, or at least not paying too much attention to it.

For what its worth, at less than 40 deg. it takes 8 or 9 blocks with 2 traffic lights for the trans to warm up for me every morning.. i can pin point the moment almost exactly that i can accelerate with no delay.. I know, wierd, but true..

[Motohip]

My car does this once in a great while when it's cold and only once per incident. It also doesn't always seem to be shifting into neutral when it's cold causing a rough idle.