[fishbowl88]

Hey guys, thanks in advance for any insight provided.

I bought a 2008 328i AT RWD about two months ago from a dealer. It has 92k miles on it, no accidents, and Im the 3rd owner.

Ever since I purchased it, I always felt like the automatic trans was a bit jerky. It also seemed to slow the car down a bit on its own when it was in 1st, 2nd, or 3rd. It coasts just fine in 4th and above. After reading several forums, it seemed like a lot of people with this trans felt it was just a bit jerky too so it seemed pretty normal.

Today I was driving around town probably not going above 3rd, and things started feeling a bit weird, as if something was slowing the car down. Then it started lagging substantially when going between 2nd and 3rd. From a stop, Id get going, smooth from 1 to 2, but then from 2 to 3 the RMPs would kind of hold and then a few seconds later it would shift into 3.

This happened probably 10 more times until I got onto the highway and got up into higher gears. Since then, its gotten back to being pretty smooth, but Im still concerned.

Does anyone know what could be causing this? Or has anyone encountered this problem before? I have an appointment on Wednesday at the dealership. They say the diags are going to be 170, and go towards any repairs necessary. I also have a basic warrant through CARS Protection Plus that is still active and would cover the drivetrain if that were an issue.

And anything to look out for as far as getting screwed by the dealership?

Thanks!
Andrew


Edit: Added in that its Automatic and RWD.

[Underground6t9]

No lag on 328i as it doesn't have turbos.

[fishbowl88]

I dont quite understand what your getting at there. I know my car doesn't have turbos. I'm talking about a delay between gear shifts, as if the transmission is not catching the next gear.

[Underground6t9]

You said you had lag, I didn't realize you meant your car felt slow.

[fishbowl88]

Yah I meant lag between gears. Its all good.

[Underground6t9]

I wouldn't worry about it till you get a diagnostic

[N54B30A]

It sounds like the CDV. Its meant to delay clutch engagement and reduce drivetrain shock, but it creates massive jerk between gears. You can either delete it entirely or run a modified one that is bored out to match the input and output clutch lines. I've done it on every bmw I have owned and its been amazing every time.

[fishbowl88]

What is the CDV and where could I learn about modifying it?

Oh and its an automatic. Not sure how I could have forgotten to mention that.

[AllBlackBimmer]

Turbos? CDV? C'mon people really? Do people even read posts?

Obviously not Turbos or CDV as it is a 328 not 335, and is an AUTOMATIC...

OP - Automatic gearboxes in these cars are pretty decent, However, it doesn't mean there aren't problems with them. It could be a few things - something as simple or dumb as the adaptive tranmissions and they way it was driven vs. the way you drive it. Look for the reset procedure online... you like how the gas pedal down without the car on or something like that (I have a manual so Im not sure how to, but I know you can)

At 90k+ miles, if it has never had the trans fluid change you MIGHT want to look into it. There are many mixed opinions on IF you should even change it now at this point IF it hasn't been regularly changed before... do it at your own risk, but if you have trans problems already, changing the fluid would be worth a shot.

[Mr. Toad]

I'm not sure from your description whether I have a clear understanding of what you're experiencing, but read this, as your problem may be similar to something I experienced:

http://www.e90post.com/forums/showth...1#post18366211

[rothwem]

The trans will hold gears when its cold to make the motor warm up faster. Its weird and makes it feel like there's something wrong with the transmission.

It also will downshift when you're slowing to match engine speed, so it'll jerk a little bit when slowing.

I would try changing the fluid, it made a huge difference on my car. Its kinda of a pain in the ass on an AWD car, but it shouldn't be too bad on a RWD one like yours. The fluid, filter, and gasket kit is under $200.

[ThatRWD]

I have a feeling your just having normal behavior, let me give you some examples. The slow down your having sounds alot like coast braking (that might be the wrong term, I'm forgetting the actual term, it's been used a fair bit on this forum, someone will correct me or just search about transmission issues). Engine braking I think it was. It's normal. Idk about you but I have some m3 suspension parts on my car and in 1-3 I can often feel the friction of the engine braking in my steering wheel. Just bearly.

The jerkiness could be because on a cold start the trans holds grears longer and 1-3 in general arn't that smooth on our cars as 4-6. If your driving in bumper to bumper for a little bit the gears all get a bit rough when shifting. 92k ... change your fluid and do the mechatronics while you are at it. Reset adaptations. Don't bother going to the stealership no guarantee they will do any of this other than the trans fluid and will just tell you the work has been completed and that it's all normal. I'd say just reset all adaptations, leave the battery unplugged overnight by morning all adaptations will have been cleared out.

You just bought the car from the stealer, they shouldn't be charging you $170 for a diag. Stay away from the stealer until you learn what work is truly necessary from them and at that point just tell them I need x or y done.

edit: hmm while you are at it, do the differential fluid as well. hmm do all the fluids since you are almost at 100k

[N54B30A]

Originally Posted by AllBlackBimmer

Turbos? CDV? C'mon people really? Do people even read posts?

Obviously not Turbos or CDV as it is a 328 not 335, and is an AUTOMATIC...

OP - Automatic gearboxes in these cars are pretty decent, However, it doesn't mean there aren't problems with them. It could be a few things - something as simple or dumb as the adaptive tranmissions and they way it was driven vs. the way you drive it. Look for the reset procedure online... you like how the gas pedal down without the car on or something like that (I have a manual so Im not sure how to, but I know you can)

At 90k+ miles, if it has never had the trans fluid change you MIGHT want to look into it. There are many mixed opinions on IF you should even change it now at this point IF it hasn't been regularly changed before... do it at your own risk, but if you have trans problems already, changing the fluid would be worth a shot.

I didnt see the automatic, he must've edited it and added it in. The CDV has those exact symptoms.

[N54B30A]

I would definitely do a tranny flush as well as a new transmission filter. I did it on my last 335i which was an auto and it got rid of the jerkyness. I ran the Redline ATF and never looked back. The transmission filter and the magnets were all coated in metal at 60,000 miles

[smallseafishie]

new fluids and filter followed up with a tranny adaptation reset.

If that doesn't fix your problem, then you'll likely need new transmission solenoids.

Check to see if you have a ZF or GM transmission. I've seen a ZF solenoid DIY guide, not sure about GM.

[fishbowl88]

Originally Posted by ThatRWD

I have a feeling your just having normal behavior, let me give you some examples. The slow down your having sounds alot like coast braking (that might be the wrong term, I'm forgetting the actual term, it's been used a fair bit on this forum, someone will correct me or just search about transmission issues). Engine braking I think it was. It's normal. Idk about you but I have some m3 suspension parts on my car and in 1-3 I can often feel the friction of the engine braking in my steering wheel. Just bearly.

The jerkiness could be because on a cold start the trans holds grears longer and 1-3 in general arn't that smooth on our cars as 4-6. If your driving in bumper to bumper for a little bit the gears all get a bit rough when shifting. 92k ... change your fluid and do the mechatronics while you are at it. Reset adaptations. Don't bother going to the stealership no guarantee they will do any of this other than the trans fluid and will just tell you the work has been completed and that it's all normal. I'd say just reset all adaptations, leave the battery unplugged overnight by morning all adaptations will have been cleared out.

You just bought the car from the stealer, they shouldn't be charging you $170 for a diag. Stay away from the stealer until you learn what work is truly necessary from them and at that point just tell them I need x or y done.

edit: hmm while you are at it, do the differential fluid as well. hmm do all the fluids since you are almost at 100k

Thanks for the suggestions. The dealership that Im going to is an actual BMW dealer, whereas I purchased it from a dealer in another part of the state. Thats why I feel like the 170 for diags would be appropriate. From what ive been able to gather, it seems like I should be resetting everything and looking into getting the fluids replaced. Id like to get the technicians opinion about the fluids because my mother had had some serious issues after they flushed her automatic. Somthing about throwing it into a new ecossytem that caused issues. Cant remember exactly.

The other thing that concerned me was that when I had the issues, I also saw a light on the dash light up. I didnt see what it was immediatley, but after turning it off and lighting up the dash im pretty sure it was the DTC light.

[fishbowl88]

The BMW service center is looking it over right now. They said that they do not recommend flushing the transmission on these models at all. Apparently it just causes more issues.

[rothwem]

Originally Posted by fishbowl88

The BMW service center is looking it over right now. They said that they do not recommend flushing the transmission on these models at all. Apparently it just causes more issues.

Right, you don't flush the trans on these. You drain, drop the pan, change the filter, put the pan back on and fill.

Flushing can mess up a transmission because some machines push the ATF through the system backwards (?) which can mess it up somehow. I've also heard that some flushing systems use a solvent, which can also muck up your car.

[cybermgm23]

I was having jerky shifts, a sluggish throttle and a rough idle in gear and I cleaned the MAF sensor and it all went away. Now my car is buttery smooth like it was new.

[fishbowl88]

Originally Posted by cybermgm23

I was having jerky shifts, a sluggish throttle and a rough idle in gear and I cleaned the MAF sensor and it all went away. Now my car is buttery smooth like it was new.

MAF sensor?

[cybermgm23]

Originally Posted by fishbowl88

MAF sensor?

yes, the MAF sensor (Mass Air Flow) is responsible for the air/fuel mixture in your engine. If it's dirty it will send inaccurate info to the computer thus causing a lean condition which can cause wonky shifts, an uneven throttle response and rough idling. It's located on the intake duct right behind the air box. It is a very sensitive sensor but needs to be to do it's job correctly. They're about $300 new. When you take it out, handle it with care! Wear rubber gloves. Spray the two silver wires on the side of the sensor with MAF cleaner liberally then let air dry. DO NOT TOUCH THE SILVER WIRES WITH ANYTHING! Reinstall and fire it up, hopefully you'll have as good of results as I did. Lots of times these things get screwed up when some genius uses carb cleaner or electrical contact cleaner on them. Don't do that. I used CRC MAF Sensor cleaner I bought at the local auto parts store. Costs about $8 and 15 mins of time. Wish I knew about this months ago.

[fishbowl88]

Originally Posted by cybermgm23

yes, the MAF sensor (Mass Air Flow) is responsible for the air/fuel mixture in your engine. If it's dirty it will send inaccurate info to the computer thus causing a lean condition which can cause wonky shifts, an uneven throttle response and rough idling. It's located on the intake duct right behind the air box. It is a very sensitive sensor but needs to be to do it's job correctly. They're about $300 new. When you take it out, handle it with care! Wear rubber gloves. Spray the two silver wires on the side of the sensor with MAF cleaner liberally then let air dry. DO NOT TOUCH THE SILVER WIRES WITH ANYTHING! Reinstall and fire it up, hopefully you'll have as good of results as I did. Lots of times these things get screwed up when some genius uses carb cleaner or electrical contact cleaner on them. Don't do that. I used CRC MAF Sensor cleaner I bought at the local auto parts store. Costs about $8 and 15 mins of time. Wish I knew about this month ago.

Thanks for the suggestion! I'll try it out.