[jbusch2021]

I don't know how else to explain it... but has anyone else experienced this? 428i xDrive GC, when in sport mode, after heavy acceleration, I lift my foot off the accelerator and the RMPs remain constant, even while the car is slowing down. I would expect it to upshift a gear or two, assuming I'm done accelerating and ready to cruise at a given speed because I took my foot off the gas.

I've resorted to shifting over to manual shifting and upshift a couple gears to get my Tach backed down from nearly redline.

I've got an appointment with BMW tomorrow, hoping for a software update to resolve, unless of course this is normal, in which case I think it's a mistake.

[jeffc83]

I thought it was supposed to hold the revs. It's great for hilly areas and sharp curves!

[STR8-6IX]

Originally Posted by jbusch2021

I don't know how else to explain it... but has anyone else experienced this? 428i xDrive GC, when in sport mode, after heavy acceleration, I lift my foot off the accelerator and the RMPs remain constant, even while the car is slowing down. I would expect it to upshift a gear or two, assuming I'm done accelerating and ready to cruise at a given speed because I took my foot off the gas.

I've resorted to shifting over to manual shifting and upshift a couple gears to get my Tach backed down from nearly redline.

I've got an appointment with BMW tomorrow, hoping for a software update to resolve, unless of course this is normal, in which case I think it's a mistake.

this is normal. it holds revs ridiculously high.

unless I am going around a bunch of tight turns or doing full throttle pulls, I just keep it in drive. the normal mode is more ideal for most driving conditions.

[cozye]

Yep. That way it stays in a good power band when spirited driving on curvy roads. That's why it's sport mode. Wonderful transmission. You can always paddle shift it if you move on

[JJS]

Or drive MT. Your choice of any gear and rpm, sport mode or comfort.

[HighlandPete]

Originally Posted by jbusch2021

I don't know how else to explain it... but has anyone else experienced this? 428i xDrive GC, when in sport mode, after heavy acceleration, I lift my foot off the accelerator and the RMPs remain constant, even while the car is slowing down. I would expect it to upshift a gear or two, assuming I'm done accelerating and ready to cruise at a given speed because I took my foot off the gas.

I've resorted to shifting over to manual shifting and upshift a couple gears to get my Tach backed down from nearly redline.

I've got an appointment with BMW tomorrow, hoping for a software update to resolve, unless of course this is normal, in which case I think it's a mistake.

Depending on how you lift the accelerator, it can suppress the upshift. It is normal to do so, has had this feature through the generations of gearboxes with transmission management.

Here's an example of the description for the 6HP series gearboxes. And totally normal for the 8HP gearboxes.

"The intention to apply the brakes can often be anticipated from the accelerator pedal being rapidly released to the zero position. If such an action is detected, the upshift is suppressed for as long as the accelerator pedal is in the zero position and the vehicle is in overrun mode."

[HighlandPete]

Originally Posted by jeffc83

I thought it was supposed to hold the revs. It's great for hilly areas and sharp curves!

Exactly, it is supposed to happen. We have control of how and when, by how we use the accelerator and brake pedal.

[Slickz]

Lower gears have more torque, higher gears have more power. It is just trying to keep you in a lower gear to give more throttle response/quicker acceleration should you decide to put your foot down, rather than have to change gears and lag a bit.

[jeffc83]

Originally Posted by Slickz

It is just trying to keep you in a lower gear to give more throttle response/quicker acceleration should you decide to put your foot down, rather than have to change gears and lag a bit.

Which is completely the opposite of Caddy/GM and their setup....one thing that always disappointed me; it shifted like a granny always dogging it, lol. (plus that HUGE delay when just trying to accelerate) Manual mode was the only way to go, sport mode was just funny.

[spuntyb]

Originally Posted by jbusch2021

I don't know how else to explain it... but has anyone else experienced this? 428i xDrive GC, when in sport mode, after heavy acceleration, I lift my foot off the accelerator and the RMPs remain constant, even while the car is slowing down. I would expect it to upshift a gear or two, assuming I'm done accelerating and ready to cruise at a given speed because I took my foot off the gas.

I've resorted to shifting over to manual shifting and upshift a couple gears to get my Tach backed down from nearly redline.

I've got an appointment with BMW tomorrow, hoping for a software update to resolve, unless of course this is normal, in which case I think it's a mistake.

I've had the car in M/S before (and NOT using the paddles) and accidentally tapped the (-) paddle without realizing and then bolted from a stop and revved to approximately 1,000,000 rpms for a few hundred feet before realizing what happened. You're sure you weren't already in M/S and tapped a paddle by accident?

[HighlandPete]

Originally Posted by Slickz

Lower gears have more torque, higher gears have more power. It is just trying to keep you in a lower gear to give more throttle response/quicker acceleration should you decide to put your foot down, rather than have to change gears and lag a bit.

I'm reading the OP is not having a problem with higher revs from Sport mode, but the accelerator lift off. Say when reaching a specific speed, or following a burst of acceleration, and expecting the box to change up a gear or two.

Two different characteristics, higher shift points (Sport mode or M/S) and shift suppression. How we lift off the pedal controls the up shifts. The same gear change suppression can occur in any auto mode, if we lift off quickly to zero throttle input. It is not just a Sport mode feature.

[jeffc83]

Originally Posted by HighlandPete

I'm reading the OP is not having a problem with higher revs from Sport mode, but the accelerator lift off. Say when reaching a specific speed, or following a burst of acceleration, and expecting the box to change up a gear or two.

Two different characteristics, higher shift points (Sport mode or M/S) and shift suppression. How we lift off the pedal controls the up shifts. The same gear change suppression can occur in any auto mode, if we lift off quickly to zero throttle input. It is not just a Sport mode feature.

He did say "when in sport mode"...

OP, can you clarify if this happens to you when in COMFORT as well?

[thakid22]

Originally Posted by jbusch2021

I don't know how else to explain it... but has anyone else experienced this? 428i xDrive GC, when in sport mode, after heavy acceleration, I lift my foot off the accelerator and the RMPs remain constant, even while the car is slowing down. I would expect it to upshift a gear or two, assuming I'm done accelerating and ready to cruise at a given speed because I took my foot off the gas.

I've resorted to shifting over to manual shifting and upshift a couple gears to get my Tach backed down from nearly redline.

I've got an appointment with BMW tomorrow, hoping for a software update to resolve, unless of course this is normal, in which case I think it's a mistake.

There are 3 different shift logics that apply to your situation.
1. Upshift Suppression - Due to quick reduction in throttle input. Lift off the gas too quickly and the trany will hold the gear in anticipation (ready to accelerate again with little delay) of you reapplying the gas.
2. Cornering Upshift Inhibitor - Upshifts can be dramatically delayed if you have any steering angle dialed in. In other words, if the steering wheel isn't pointed straight, the car will hold a lower gear because it knows the car is cornering. This prevents upshifts from disrupting chassis composure. This also makes the drivetrain more responsive at corner exit, because it doesn't have to downshift when you power out of the corner.
3. Grade Logic - Is here to reduce excess shifts on up or downhill grades. It also provides engine braking for downhill descents, and more power for uphill ascents. But in the lower gears it can be fooled. If you accelerate hard, then release the gas pedal, momentum can briefly continue to accelerate the vehicle. This, even with your foot off of the gas pedal. This can be misinterpreted as a downhill slope by the computer. A downshift or delayed upshift can occur. You are most likely to experience this on a road that isn't perfectly flat. But it can occasionally happen on a flat road too, if certain parameters are at play.

1 and 2 are most common. None of these are malfunctions. Rather, it is simply the programming of the transmission. That being said,I have long wished for alternate programming of the 6spd and 8spd Automatics.

Sport mode does have a tendency to hold the revs seemingly high, even at constant speeds.
If I were programming these Autoboxes, I'd add a mode between Regular and Sport.
It would hold gears during acceleration like sport mode. But it would upshift to top gear like regular mode (during steady state cruising). This new mode would also be very sensitive to throttle input and downshift easily and quickly. Today's ZF and SAT autos shift quickly and smoothly enough that I don't see the point in holding the revs artificially high, atleast not during steady state cruising. Sport mode is fantastic when speeds are constantly rising and falling. But at a constant speed, it just wastes gas and makes the engine sound labored.

[Billfitz]

When cruising sport puts the tranny a gear or two lower than normal, so when you want to accelerate the engine's already in the peak HP range and turbo lag is minimized. But it shouldn't keep the engine anywhere near redlining. If it did then acceleration would be compromised, because it's got no more to give. If that's actually the case, and not a wee bit of an exaggeration, you need to have it checked out.

[Orion4]

"revved to approximately 1,000,000 rpms for a few hundred feet before realizing what happened."

Hyper-drive malfunction due to too much caffeine in the Flux Capacitor.

[dkirsch78]

As everyone else here has said, it is indeed normal. What I'll say for myself is that after adding MPPSK, I'm pretty fine with Comfort mode most of the time. Prior to that I was in Sport constantly, but found myself manually upshifting to bring down the rev.

[NewM3driver]

In sport it will hold gears for a bit more time before upshifting.

[jbusch2021]

Thanks for all the feedback guys, my first BMW, and was concerned maybe there was something going on with it that shouldn't. I just had it in for scheduled maintenance and mentioned my concern, they took it out and verified everything was in order. On my drive home I did check it out a little more thoroughly, and if I get on the brake and slow it down, it responds as I'd expect. I was just surprised at how long it would hold the higher RPMs when I got off it and didn't hit the brake. I'm getting used to manually upshifting when I'm done stomping on it and just want to cruise.

[eluded]

That behavior is normal. Sport mode will hold the RPMs if you're driving the car hard. I don't often drive automatic BMWs but I did recently and I saw similar behavior in sport mode while getting an amazing 13 miles per gallon.

[HighlandPete]

Originally Posted by jbusch2021

Thanks for all the feedback guys, my first BMW, and was concerned maybe there was something going on with it that shouldn't. I just had it in for scheduled maintenance and mentioned my concern, they took it out and verified everything was in order. On my drive home I did check it out a little more thoroughly, and if I get on the brake and slow it down, it responds as I'd expect. I was just surprised at how long it would hold the higher RPMs when I got off it and didn't hit the brake. I'm getting used to manually upshifting when I'm done stomping on it and just want to cruise.

Good to see you have come back with the garage outcome and clarification of when it happens.

Remember it is how you lift off the gas after "stomping on it", will either supress the upshift you expect, or allow it to happen.

Experiment with the way you use the accelerator, as you can control how the 'box works in many situations. Same applies to how you use the brakes, 'brake evaluation' also has its place in holding gears or instigating down shifting.