Why is it that sometimes when I drive down a road the tranny will downshift automatically into sometimes (gasp) 3rd gear doing 60 mph or so, and other times it stays in 6th gear?

I've noticed this on my 530 and now on the 645Cic.

Same hill, same weight in car, same speed, both times in "D", engine and trans up to temp both times.....


And can anyone explain to me why the trans must hang on to 1st and 2nd until 3000 rpm sometimes when I barely have my foot on the gas in D?

This 645 has great low end, I love it when the trans just goes bang-bang-bang through the f=irst 4 gears. I hate it when it won't shift out of second and I'm trying to let my foot off the accell and it still won't shift and then I have to go into manual mode just to shift into 3rd gear at a reasonable RPM.

This is truly random, I could see if I had been driving in a spirited fashion just beforehand and the computer held onto sport shift settings for me out of pre-programmed logic.

But I can be plodding down the road not revving it above 2000 rpm and at the next light it revs past 3000 rpm in 1st and 2nd.

What gives???

 

I had this problem until I upgraded to 16.3 software - I'm running 17.1 now. Since the upgrades, it occurs much less often and I am pretty sure only when I depress the accelerator at a somewhat faster rate. It seems to be driven not by how far you depress it, but by how fast. Even then, it doesn't just hang at 3+K RPM indefinitely, it up-shifts fairly soon, especially if I lift off a bit.

 

Never had a similar issue w/ my steptronic, but then we don't have any hills here in New Orleans! Seriously though, does sound like something a software update will take care of. You don't indicate when your 2005 645 was built, but I'd bring it to the dealer for an update. I had the "slam" issue and got updated a couple of weeks ago and the issue has been resolved.

 

First of all i don't have this problem, but my car is built in june 2005 so... Now please excuse me! can someone explain to me how a transmission slam occurs? What does it happen with the car and gearbox? Describe the proccess plz...10x

 

The "slam" was well documented here and BMW had a service bulliten out about it. It is really a hard/harsh downshift from 2nd to 1st. Happened when you came to a rolling stop, but never completely stopped. When you hit the gas again, the transmission would make a very hard downshift to 1st as you tried to accelerate. It was corrected w/ a software update, in my case going from version 15.0 to 18.x. Being a June 2005 build, your car likely came from the factory w/ updated software to avoid the problem.

 

The "slam" was well documented here and BMW had a service bulliten out about it. It is really a hard/harsh downshift from 2nd to 1st. Happened when you came to a rolling stop, but never completely stopped. When you hit the gas again, the transmission would make a very hard downshift to 1st as you tried to accelerate. It was corrected w/ a software update, in my case going from version 15.0 to 18.x. Being a June 2005 build, your car likely came from the factory w/ updated software to avoid the problem.
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Thank you alot! I got the ideea... It seems i don't have it either! It would be so more interesting if you could just check your cip vers for youself, on the idrive screen. I wonder what vers do i have?!?
ps: how do you reboot the idrive? (ctrl alt del) when u reboot the settings are not erased right?

 

Seeing the version would be nice, but can't be done. If you tell us your build date (inside the door on drivers side) we could venture a guess. The reboot is only possible on cars with Navigation (which I don't have). Do a search but it is something like holding down the CD eject button, the DVD eject button and pressing the off/volume knob all at the same time.

 

I could be wrong but part of what determines shift points is your past driving habits. If you drive aggressively it tends to hold gears. I've been very happy with both steptronic cars I've owned. Especially the 325 hp one

 

I had the exact same problem, and it was irritating the hell out of me. A software update fixed the problem completely. It's like a new transmission now-- no more "hanging onto" lower gears to 3,000 rpm all the time. Low acceleration shifts are now at 2,000 or less, and perfectly smooth.

-RAI

 

Never have had that issue in my 6er. In the D mode it behaves quite nicely - docile as it should be unless I ask it for more. Only in DS or "Sport" D do I get aggressive up (and down) shifts as I believe it should be. I have been thankful that I have not fallen prey to the Step issues that a few others have or had. I started out with CIP 15.2 and am currently on CIP 16.2