[JDS]

Morning everyone. I have a 2021 LCI X3M and just recently noticed that on the motorway, it is not upshifting into 8th gear like it normally does. Anyone else experienced this before?

A few details to help:
I tend to drive on the motorway in comfort mode
Shift pattern set to "1", i.e. the least aggressive
Speed in the mid-seventies (mph)
Road is generally mildly downhill most of the way, so it doesn't need to pull hard.

I drive the same route every day Monday to Friday and this has only just started to happen. It basically won't shift up to 8th. If I "force" it into 8th using one of the paddles, it stays for 5 seconds or so and shifts back to 7th.
It will stay in 8th if I put it into manual shifting and it does fine.

So just wondering what might have changed that could be causing it to not push into 8th.
I am due for my oil service, but can't imagine this is a factor.

Thanks for any help/thoughts.

James.

[BMWX3MCompUK]

I have the same 'issue' when cruising around 70-80mph.

if i leave in full auto it'll often drop down to 7th on the slightest incline sometimes. i just manually pull the paddle and shift it up to 8th.

8th gear is is essentially an overdrive gear.

in 8th crusing at 70-80 im bearly pulling 1500rpm so very little torque down there as mine is completely stock atm.

[JDS]

Thanks. Mine is stock too, however it used to be fine in 8th, so I am trying to figure out what might have changed. As I mentioned, it won't stay in 8th, if I flick it into 8th with one of the paddles, whilst still in full auto mode, it reverts to 7th.

I am with you on the inclines, it doesn;t take much. But on downhill sections of the M1 where I know it would normally be in 8th, it is now running in 7th.

The only other change I can thn of is that I recently had to fill it up with regualr unleaded as opposed to super. I can't imagine the ECU would be that sensitive and made an adjustment like this so fast?

James.

[Jolbex]

Maybe it does. Low-speed knocking detected? Leading to reduced power....leading to gearbox behavior?

[JDS]

Thanks, perhaps you're right. As mentioned above, it can be a fine margin between it being in 7th or 8th anyway, so if it is sensing lower power from the lower fuel grade, perhaps...

[BMWX3MCompUK]

Most modern cars ecu's auto adjusts power according to the fuel in them they're sold worldwide and have to adjust depending on octane and ethanol you get in each market, maybe as you're running regular petrol and you have slightly reduced torgue so holding 7th gear longer.

[thestimp]

I have been told before 8th is for 80 (cruising), its strictly a flat highway gear above 65

[strohw]

How fast are you going when it does this?

[JDS]

I appreciate everyone's insights as to what 8th gear should or shouldn't do, but my point/question is about what might have caused the definite change i am experiencing. I categorically know that on my usual drive, at the same conditions, the car would always upshift to 8th, and now it is doing it in 7th. It won't automatically upshift to 8th and won't stay in 8th if put into that gear when in full automatic mode.

I am trying to understand what might have caused the change in the car's behaviour. Although it logically makes sense, I would be surprised that a change from 97 RON superunleaded to 95 RON standard would make this much difference. For reference, I have now switched back to superunleaded and the car is still exhibiting the same preference for 7th gear over 8th.

I am also due for an oil service. Has anyone had any experience of the car backing off a little on power when approaching the end of the oils's life? Could this be a factor? I will ask them to look into it, but as we know, BMW techs struggle to find much more blatant/obvious issues that we report, so I won't hold out much hope here.

[BMWX3MCompUK]

did you have the initial 1200 mile service done? that includes a gearbox oil change. they're shipped with extra thick oil from the factory which is replaced with the standard gearbox oil.

Not sure what the gearbox oil intervals are but shouldnt need another one in less than 3 years?

[JDS]

Quick update on this. I took my car on for its oil service yesterday (12,000 miles on the clock), and unsurprisingly BMW (Sytner Nottingham) were not able to identify anything.

They did take it out for a drive (18 miles according to my BMW App), but reported back to me via the SA that "it's not supposed to shift into 8th until you hit speeds above 75 mph). This is absolute BS. On my regular commute, the car would shift into 8th around 58-60 mph if I was joining the motorway in comfort mode and in a lesiurely rather than 'spirited' manner.

I have been doing some research into this and it has been reported by quite a few owners of S58 engined cars. This issue seems to be with the OPF getting "stuck" in a regen mode. OPFs are differnet to DPF in how they need to be regenerated apparently, and this issue is casued by excess soot on the OPF than has not been cleared away.

After some advice from an owner on the G80 forum, I was able to clear up the issue for now, but will continue to keep an eye on it.

https://g80.bimmerpost.com/forums/sh....php?t=2013153

I'll report back if I continue to have further issues.

James.

[ajbM4cab]

Just to help here. Mine drops into 8th from 65-70 no probs. However the slightest depression on the accelerator will drop to 7th and even 6th sometimes. Even when in the most eco friendly settings.
A manual push to 8th is often required.

The issue I am having is that, when in auto, every time I kick down to overtake it hold the lower gear far too long after letting off the accelerator.
Seems like an age before falling back to a higher gear. Gear selector set to setting 1 too.
Anyone else.