my theory on all these tranmission issues

mallards · Nov 14, 2003

does anyone think that all these automatic transmission (steptronic) problems are caused my the manual downshift in steptronic mode?

because i believe (last time i checked) is it bad to down shift with normal auto transmissions ...

does anyone thing maybe BMW didnt design the transmission with those downshifts in mind or something stupid like that ...

it just seems a little strange that so many people are having problems with the 5 speed auto steptronic trannys ...

what ya think?

Ben

Black330 · Nov 14, 2003

I don't have any problems.

bmwrocks · Nov 14, 2003

I don't have any problems either, but I mostly disagree with your theory mallards.

I am sure BMW didn't throw the tranny together without thinking thru all the possible uses of it or the forces it could encounter under the most adverse usage or abuse. Also I am sure they thouroughly tested it under adverse conditions. It is also computer controlled so it won't downshift when the downshift would cause forces out of the spec limits of the tranny.

On the other hand, it is computer controlled so it would be susceptible to computer bugs.

But they definitely considered downshifts when they designed it. I would bet your car on that.

jrt67ss350 · Nov 14, 2003

Downshifting a "non-steptronic" automatic transmission in any car by selecting a lower gear manually will not harm the transmission. This is a very common misconception. The main reason lower gears are manually selectable in a "non-steptronic" car is so that you can downshift manually, especially when you need to decelerate down a steep grade.

Think about it - if you are driving along in Drive at 50 mph and you floor the car, it's going to downshift based on engine load, throttle position, and transmission governor speed. This "allowed" downshift is absolutely no different than moving the gear selector from Drive to 3 or 2, it's just automatically achieved. My Camaro has a 3-speed automatic in it, and when the car needs to downshift, I have to do it manually most of the time since the cable that tells the tranny how far the throttle is depressed is not hooked up. Modern automatics will not let you shift into a gear that would over-rev the engine - hell, even my '67 Camaro with it's completely mechanical automatic won't let you select first gear if it would result in the engine running over about 4000 rpm. If anything, downshifting a manual car is more dangerous - you actually have the potential of selecting a gear that will result in over-revving the engine.

In light of this, I really don't understand the whole Steptronic thing. The point of it is to give you control over your shifts, right? Well, you can manually downshift any automatic transmission - you don't need "Steptronic" to do that. The only thing Steptronic is good for, in my opinion, is for starting in second gear if it's icy (but you've got traction control anyways) or for shifting earlier than the computer would if you left it in Drive (and I have no idea why you'd want to do that). I think it's a marketing gimmick.

Kirby · Nov 14, 2003

A couple of thoughts -

It wouldn't suprise me if it is indirectly related to Steptronic. Not the actual manual shifting, but what if the reported clutch plate problem is aggravated or actually caused by higher engine RPM = higher torque converter speed and pressure? Since Steptronic lets you run at a higher RPM, this could be a factor.

A marketing gimmick? To some degree , yes, I agree. But there are differences in Steptronic as compared to a classic automatic stick shift:

1. The classic automatic transmission does not have anything like the Sport Mode, which maintains full automatic shift point control, but causes it to occur at higher RPM.

2. In Manual mode, it is just a flick forward to downshift, or a flick back to upshift, sorta like an SMG (yes, I know that SMG is totally different mechanically). You don't have to "find the notch" as you would on a classic automatic. Also, if you wind it out on a classic auto transmission and then back off the throttle, it will shift up from 1st to 2nd, or 2nd to 3rd. The Steptronic Manual mode NEVER shifts up automatically unless you redline. This is ESPECIALLY useful on twisty hilly roads where you want to stay in 3rd or 4th gear, for fun driving naturally. When used specifically for this (I love driving these types of roads - car or motorcycle), the auto feels and responds almost identically to a manual. You get that immediate accelerate/engine braking response. A normal automatic would have shifted up and you loose the engine braking.

Marketing - yes, but there is a fun factor to it.....

mallards · Nov 14, 2003

........ It wouldn't suprise me if it is indirectly related to Steptronic. Not the actual manual shifting, but what if the reported clutch plate problem is aggravated or actually caused by higher engine RPM = higher torque converter speed and pressure? Since Steptronic lets you run at a higher RPM, this could be a factor ...... posted by Kirby

thats what i was trying to get to ....

im wondering if the steptronic has any connection to the problems

Ben

///M SPEED · Nov 14, 2003

Black330 said:

! I don't have any problems either. Seems to be the newer 03' and 04's that seem to have the most problems.

jrt67ss350 · Nov 14, 2003

Kirby said:

I understand the convenience of the flick up to upshift, flick down to downshift - that is nice. Having driven a 2000 323i Sport with the Steptronic, I can personally attest to that, and I did find Sport mode to be very nice. However, a lot of cars have a sport mode, without the whole steptronic thing. I also understand the benefits of being able to hold the transmission in a gear as you describe. However, any automatic will do that. Example - I'll use my 37 year old car with it's old technology tranny to illustrate. I'm driving down a mountain road in third gear, coming into a sharp turn. I move the gear selector from 3 (Drive) to 2. The transmission instantly downshifts, bringing the rpms up and helping to slow the car. As I go through the turn, it turns into an S curve, and I keep the gear selector in 2 - the tranny stays in second gear and the rpms stay right in the power band of the engine - 3000 rpm - even with the foot off the gas. I can now directly modulate my speed with the gas pedal and take off instantly as I come out of the curve. I hit my 5500 rpm redline and shift into third. Any automatic transmission will hold any gear (less than Drive) it is selected at, even if you completely take your foot off the gas. My Camaro does it, my girlfriend's Grand Prix GTP does it, my parents' Impala LS does it - all automatic cars will do it.

Having spent lots of time behind the wheel of the Steptronic, my Camaro, and my girlfriend's GTP, I just don't think the Steptronic is anything special - it doesn't do anything that any automatic tranny with a sport mode can't do. It's just got a fancy electronic shifter that you can flip up and down quickly. The shifter is nice, but I think it's all a marketing ploy. Lots of people that have steptronic-equipped BMW's think they have some special transmission that can do things a "normal" automatic can't. That's just not true.

///M SPEED · Nov 16, 2003

jrt67ss350 said:

Who ever said it was "special"? I don't believe anyone here thinks that having a Steptronic transmission is anymore special than a standard transmission. We are just discussing the transmission on this thread and some of the problems some are having with them. I do not know why you think some here or some BMW owners think having a Steptronic transmission is "special". That is just your opinion about the Steptronic tranny.

Do you think anyone with the old Duel-Gate transmissions in the late 60's-early 70's thought it was something special? It was a pretty neat tranny and a lot who had them thought it was special because most did not have them. The Steptronic transmission is just the newer automatic BMW equips their cars with. Whether someone thinks it special or not it just his or her opinion anyway.

BlackandSand · Nov 16, 2003

mallards said:

Back to the original question. BMW must have built the Steptonic with downshifting in mind. If you market the Step as "like" a manual, you have to expect people are going to downshift. I can't imagine BMW, known for their high design, creating a car that is so marvelously engineered in so many ways, falling flat on their face because they didn't think people would downshift. Plus, they've been making the Steptonic for how many years now?

Here's my theory. There was a problem at the Regensburg plant on one of the lines earlier in the year.
http://www.bmw-werk-regensburg.de/regensburg/htdocs/english/index_home.html
I don't think they make all the 3's here but I'm pretty sure they make all the convertibles here, and it seems to be more a convertible problem. It's also curious to me that BMW came out with a revision in the car (the October ver. with available SMG) less than 6 month's after it's initial production.

No matter what, I think BMW needs to confess they've got a problem, and address it NOW.

Does anyone feel there is too much "lag" in the tranny when using it in D or fully automatic, especially from a stop? By lag I mean an unusually long time between hitting the gas and feeling a response. I have this problem, and have also had some of the problems Kirby's had. If no one else feels a lag could my "lag" be a harbinger of things to come? Just wonderring.

outpost22 · Nov 16, 2003

Our car is too new to know if there are problems yet with the Step. So far so good. I would hope BMW thouroughly tested "downshifting" in their preparation for delivering these cars.

The Steptronic is a nice choice for our situation. My wife has been driving her "stickshakers" for the last 15 or so years. She finally wanted a car with an auto. I can't blame her as there are just a lot of days where she works 10 hours and doesn't want to dance with the shifter driving home. When we go for a nice drive, I can enjoy the "manual" mode and there is no way any of my previous autos shifted life the Step. You always have to check the "detent" on a regular auto to make sure of not 'jumping" over a gear, at least I do. The Step is very precise and easy to select each gear. It is NOT for purists, and there I believe is the "rub". It reminds me of when I first drove my brothers Ferrari with "F1" shifting. Getting used to the "paddles" was really weird at first, but it all becomes what you get used to...or like [:p]

frolf · Nov 16, 2003

bmwrocks said:

yeah, BMW really doesn't throw anything together.

Harman1 · Nov 16, 2003

I'm having the problem with the my trany, noticed it a week or so after getting my car, I've only had the car for 6 weeks. I noticed on my window sticker the trany is made in France. Do any of you know where the tranys in your cars were made.

frolf · Nov 16, 2003

Harman1 said:

in steptronic mode? you should allow your car to break in before you start exercising the steptronic mode. if this is an auot we are speaking about.

bmwrocks · Nov 16, 2003

Re: Re: my theory on all these tranmission issues

BlackandSand said:

I feel this "lag" you are speaking of, and I don't have the slipping tranny. Although I only get it when I press the accelerator gently from a stop. Never when in motion that I have noticed. I attributed it to the "fly by wire" throttle on our cars. But now that you mention it, I definitiely notice it and am worried about it.

Anyone else have this with their auto tranny equipped vehicle?

I am going to try just revving the engine in neutral and see how the response is from idle. If it responds quickly in neutral, then I am going to show it to the dealer. You try it too BlackandSand.

Kirby · Nov 16, 2003

Not related to the specific slipping problem I have, I never really mentioned the my thoughts about general 'lag' on the transmission. Ever since I got the car, I felt that at low RPM (under 2500 or so) the transmission felt 'soft' to respond. I just figured that was how it was intended to work, and since it was my first BMW, I had no experience to compare it.

When they gave me the '01 325 loaner to drive, I noticed a definite difference. When pulling out, that 325 felt like it had MORE power than my 330. I noticed it and played around with it for a bit. But above 2500 RPM or so, and especially at highway speeds, it felt less powerful, as you would expect. I just attributed it to programming differences.

As far as the score goes, the SLIPtronic thing happened 3 times this week. [:(]

Kirby · Nov 16, 2003

I did some Web searching on the 2004 3 Series and came across this article that helps to explain why 2004 cars are having problems, but not 2003. Here is the link to an article: http://peachtreebmwcca.org/BMWPressNews/showquestion.asp?faq=5&fldAuto=267

In part it says:
What makes the digital ramp-up so exciting is the fact that the 2003 model year BMW 3 Series is quite comparable to the start of a new model, involving a wide range of modifications and improvements for the new model year. With the 2004 BMW 3 Series Coupe and Convertible, for example, both the front and the rear end have been redesigned and the engine as well as the transmission have been modified in technical terms, not to mention the wider range of standard features now offered to the customer.

BlackandSand · Nov 16, 2003

Re: Re: Re: my theory on all these tranmission issues

bmwrocks said:

I just compared reving the engine in neutral vs. slow start in D, fast start in D, slow start in M, fast start in M.

Yes, there is a little lag in neutral, certainly more than in a car where the pedal is directly coupled to the throttle. I can't really say there is TOO much difference between reving, starting in D, or M, but then my car was warm. When I REALLY sense a lag is from a cold start, right after backing out of the driveway. In a way Kirby's problem is an extreme example of the lag. I'm wonderring if any one else has this "lag" problem from a cold start ? There may be many of us having the same problem as Kirby but it's so slight we just shrug it off as that's how the car works.

I'd like to compare a 2004 and 2003 back to back.

donmbmw · Nov 16, 2003

I downshift in manual mode all the time with no problems. As a matter of fact, I often switch form full auto to sport then to manual and back again routinely. This transmission is a marvel of modern engineering and adds tremendously to my joy of driving. [burnout]

[driving2]

bmwrocks · Nov 17, 2003

I was thinking about the electronic throttle controls on our cars. There is going to be some inherent lag in the system just because of what has to happen:
1. Accelerator pedal sensor changes position when pedal moves (hardware)
2. New sensor position is processed by computer (software)
3. Resulting commands cause changes in engine management settings (hardware and software)

This process will introduce some transport delay from the initial hardware input to the resulting engine/transmission output. I don't what the spec is for this but I could see it in the range of a 125 ms to 250 ms response time as being acceptable.

Imagine the blank stare you would get from a service advisor if you started talking about this....... [?|]

my theory on all these tranmission issues

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