[SteeleyScott]

Hi all,

Looking for a bit of advice on this one.

I've noticed the car isn't driving smooth at all when In gear. E.g I could be driving at 30MPH, and the car will sort of feel like its jerking back and forward. Even when I have cruise control on at say 60MPH on the motorway, it's doing it then too. Speed or RPM don't appear to be moving at all, despite the jerking.

few things to point out

:-I notice it alot more on cold start and it does appear to lessen and become much less noticable say 5-10mins in to a journey.


:-It had an EGR recall last month, Honestly I can't recall if it was doing it before then or immediately after. But now very noticable.

:- Also it would appear the rear tyres are star rated, the front 2 are not.


Do any of the above generally point toward the in gear jerking symptoms i'm experiencing? And if it IS the tyres, does it generally go away once going back to all star rated? or is the damage already done?

thanks for any input on this, really appreciated.

S

[COKen]

Hard to tell by your description, but if it is engine related you should have the codes pulled to see what is going on. It could be coils, plugs, vacuum leak, etc. I'm not sure how tires would cause a backward/forward jerking motion. It could also be brakes. If you have a warped rotor or a sticky caliper. Have you visually inspected your tires and brakes?

Update: Just noticed you have diesel - probably not plugs. (c;

[SteeleyScott]

Originally Posted by COKen

. I'm not sure how tires would cause a backward/forward jerking motion. It could also be brakes. If you have a warped rotor or a sticky caliper. Have you visually inspected your tires and brakes?

Update: Just noticed you have diesel - probably not plugs. (c;

I thought tyres potentially because a few things id read online about using non star rated stressing out the xdrive and causing weird issues. BMW told me in person to always use star rated but tbh it just wasn't possible to during lockdown.

Your comment about fault codes....Im not getting anything on the dash, so assumed there'd be a problem there if it was spitting out error codes? I do have the thing to connect my pc, just never done it.


The Jerking sort of feels like im taking my foot on and off the accelerator pedal very quickly, like a stop and start motion but as i said, even when I have cruise control on and set to 40mph....no foot on the gas....still does it.

I have noticed it does it in manual or auto, always around the 1-1.5krpm range and much more noticable for the first 5 mins of driving ahead of the car warming up properly.

[HighlandPete]

If I was fault finding this myself, and suspecting tyres could be involved with xDrive, I'd simply run a test by adjusting the front tyre pressures.

I'd increase the pressure, say 5 psi, and run a short trip to see if the jerkiness is better or worse. Then lower the pressure (5 psi below the initial setting) and try again. Test to see if it is better or worse.

Pressure adjustments will be changing the Rolling Circumference/Radius of the front tyres in relation to the rear tyres. One of the adjustments should get a closer rolling tolerance, if the tyres are involved, and causing a transfer box related issue.

Just be aware the TPMS may throw a warning.

[SteeleyScott]

Yeah good shout, I tried changing the PSI drastically today. Unfortunately made no difference.

As I mentioned above it does appear to be so much more noticable on cold start and for the first 5 mins of driving. Then pretty much goes away. But for those first 5mins or so, so noticable between 1k-1.5kRPM



I've called BMW and they just say bring it in for a £150 inspection, i'm reticent to go ahead with that if I can atleast narrow down where the problem may be coming from.

That's why Im asking here really, to see if anyone has experienced these symptoms and what the problem was?

Based on the fact it goes away after driving for a bit too, does that help narrow it down?

[szvikito91]

Hi mate,

Have you managed to find out the root cause of the “jerking”? I just started experiencing the same thing and trying to find out the issue.

Cheers

[anielsen71]

Originally Posted by SteeleyScott

Yeah good shout, I tried changing the PSI drastically today. Unfortunately made no difference.

As I mentioned above it does appear to be so much more noticable on cold start and for the first 5 mins of driving. Then pretty much goes away. But for those first 5mins or so, so noticable between 1k-1.5kRPM



I've called BMW and they just say bring it in for a £150 inspection, i'm reticent to go ahead with that if I can atleast narrow down where the problem may be coming from.

That's why Im asking here really, to see if anyone has experienced these symptoms and what the problem was?

Based on the fact it goes away after driving for a bit too, does that help narrow it down?

Hi there
My F36 435d X-drive has started doing the same.
I used Xdelete to troubleshoot the issue. When disabling X-drive by opening the clutch in the transferbox, there are no studdering at any speed. Enabling the X-drive, studdering is back in the same way you describe it.

That leads me to think its the clutch plates in the transferbox that is worn out and needs a replacement. I have 191.000km on the clock now and have been running non star marked tires the last 2 years. But within 1% in difference front to rear. I have also replaced oil in the transferbox every approx 25.000km for the 91.000km I have been the owner.
I just think its a question of replacing either the transferbox or the clutch plates in it. Or use Xdelete to leave it open and run RWD instead. Doing so my rear tires will be work faster since I have noticibly less grip running RWD.

[SteeleyScott]

Very interesting. I’ve actually been out of the country for quite a while..

Came back this week. Fresh service on my 435d. BMW said it showed zero errors either but did need some software updates. Including some gear box stuff

To be entirely honest I’d forgot all about this issue till I drove the car back from the garage and instantly noticed the juddering again

As it didn’t show any errors I’m assuming now it’s not engine related and like you guys am starting to assume it’s transferbox XDrive related.

I think it sounds sensible to try and open the clutch using XDelete. As it sounds like this worked for you? Good for narrowing the problem at least. Shame it’s $150 tho!

[AndrewC1989]

I had a similar issue (but the stutter only occurred under moderate to heavy acceleration at highway speeds) and was convinced that it was the transfer case (based on my forum research and since the symptoms subsided with xDelete). I changed my flex disc, transfer case fluid, and output flange, and while it definitely made the symptoms milder, the jerking still persisted. Recently I got new wheels and tires and all symptoms immediately vanished without a trace. Not sure if this is pure coincidence and I can expect my transfer case to implode in the near future, or if the symptoms were due to something else like a bent wheel or uneven tread wear, but it's been a month and I haven't felt so much as a hiccup. Neither set of tires was star rated so I don't think that has anything to do with it.

[HighlandPete]

Originally Posted by AndrewC1989

I had a similar issue (but the stutter only occurred under moderate to heavy acceleration at highway speeds) and was convinced that it was the transfer case (based on my forum research and since the symptoms subsided with xDelete). I changed my flex disc, transfer case fluid, and output flange, and while it definitely made the symptoms milder, the jerking still persisted. Recently I got new wheels and tires and all symptoms immediately vanished without a trace. Not sure if this is pure coincidence and I can expect my transfer case to implode in the near future, or if the symptoms were due to something else like a bent wheel or uneven tread wear, but it's been a month and I haven't felt so much as a hiccup. Neither set of tires was star rated so I don't think that has anything to do with it.

For juddering, I would suspect the tires. When we run non star marked tires with xDrive, we do run the risk there may be issues. Changing to a different set, you could be back in tolerance. Remember tires have quite a wide tolerance in manufacture. With non star marked, it is a bit of a gamble, even for OE sizes.

[AndrewC1989]

Originally Posted by HighlandPete

For juddering, I would suspect the tires. When we run non star marked tires with xDrive, we do run the risk there may be issues. Changing to a different set, you could be back in tolerance. Remember tires have quite a wide tolerance in manufacture. With non star marked, it is a bit of a gamble, even for OE sizes.

Both sets of tires were Michelin AS3+ and both sets were OEM sizes so in my case I really doubt it had to do with manufacture tolerances. What I think happened was I had really uneven tread wear due to only replacing one damaged front tire rather than two at once as is recommended.

[SteeleyScott]

Interesting indeed. I've not tried Xdelete yet

Hopefully your new tyres have put you back in the tolerance as you suggested?

My issue I think may be a little different. Its a tough one to explain, the stuttering/juddering sort of feels like you're on and off the gas. But it only happens at low RPM for me, specifically between 1k-2k. and Ive probably mentioned before but to prove its not my foot I can reproduce this issue even when i've got cruise control on, say 50mph cruising in eco mode. Its jerking back and forward. You can see the torque output being affected on the sport display too.... whether thats indicative of anything who knows!

I did read the EGR valve only functions between 1k-2k rpm so my guess is its either that or the transfer box.

From memory I think im on all star rated tyres, they're the same cross axel but I think the rears may be slightly different to the fronts.