Larger wheels = transfer case issues?!

[M302_imola]

Originally Posted by sukhk527

I went from 19s to 20s a few months ago and then replaced tires on the 20s with a fresh set. Started to feel the tugging but serviced the transfer case about a month ago and no issues since. Just service it.

Hey bud, was the tugging only at very low speeds?

[sukhk527]

Originally Posted by M302_imola

Hey bud, was the tugging only at very low speeds?

I noticed it at medium speeds too. For example WOT on an on ramp from 40-70ish.

[crystalworks]

Originally Posted by sukhk527

I noticed it at medium speeds too. For example WOT on an on ramp from 40-70ish.

Ours was worst cruising ~45mph. Rarely did it at other speeds, but easily repeatable at that speed.

[RX4Pain]

Ive been lurking the board for years but I felt obligated the make this post to help others.
Red_Y_ and M302_IMOLA was spot on. I had the tugging issue upon acceleration between 20 and 40 mph (39k miles on vehicle). No codes on dash, no codes stored, nothing, it just appeared suddenly, however, I did notice it after I replaced both rear tires (had a flat on the right rear) and the fronts only had about 4k miles on them, so no need to replace those.
I changed the plugs, coils, and nothing...issue was still there. Came on this board and realized others were having this issue as well. I removed fuse #63 and the issue went away. At that point I knew I was on the right track. Vehicle was at the dealership in Augusta, GA and they said it was the tires, I said, "ridiculous", I've had that set up since since 2016 (Michelin Pilot Super Sport, 21's staggered set up) and no the tires haven't been on the vehicle since that time.
At that point I knew they were incompetent and decided to pick up vehicle and make an appt at another dealership in Athens and requested for them to change the TC and do a reset, in which they said was part of the process when doing a TC service (sorry I wasn't going to change it myself, was in GA visiting family). Don't think I would've done it if I wasn't.
I'm now Happy to report issue is resolved so if you are having this tugging, skipping sensation, do the tc service. Thanks guys!

[virtualbong]

Originally Posted by Sophisticated Redneck

I thought this too when it affected mine, same tugging and "engine missing" issues. Turned out to be the TC too. I got very lucky, just a oil change and TC adaptations reset and recalibration fixed it.

What happens is the ECU asks for a certain torque setting to be set to the front wheels. Of it's not met, it cuts the engine power for a split second and then tries again. Makes it feel like the truck has a miss/tugging sensation.

Easy way to test is just pull the fuse for the Transfer case to force it into 2wd mode. If it's your Transfer Case then it will instantly go away.

For anyone reading this with similar issues, change your oil and recalibrate the TC before replacing, there is a reasonable chance you won't have to replace the entire TC.

This is EXACTLY what is happening with my X5 after purchasing some used 22s. I started to feel this tugging at lower speeds during acceleration. I thought it was the lower links but what you guys have described seems to be exactly what is happening to me. My mechanic also thought it was my suspension so thankfully I have not replaced them yet.

How does one recalibrate the TC during an oil change? Do I just ask the dealership to do this since I normally bring it in to them to perform the oil change?

[Sophisticated Redneck]

Originally Posted by virtualbong

This is EXACTLY what is happening with my X5 after purchasing some used 22s. I started to feel this tugging at lower speeds during acceleration. I thought it was the lower links but what you guys have described seems to be exactly what is happening to me. My mechanic also thought it was my suspension so thankfully I have not replaced them yet.

How does one recalibrate the TC during an oil change? Do I just ask the dealership to do this since I normally bring it in to them to perform the oil change?

First, measure the circumference of your tires. Use a string or wire and wrap around the outside, if the front and back are off by more then one percent, recalibrating won't help for long as the ECU will continuously think the tires are slipping since they are not rotating the same speed and get caught in that loop of requesting new torque targets I mentioned above and that tugging sensation will come right back.

If circumference is within spec front to back, then call your dealer and ask as some will and some won't, mainly consider the TC as sealed unit and will not change or calibrate it, but they happily sell you a new one for 8 grand.....funny how that works.

You can also do it yourself with ISTA (what I used) and I have heard other members have been able to use the foxwell nt530 scanner with BMW software to do it also.

Otherwise call around an find a good independent mechanic that is familiar with the reset procedure and changing oil on BMW F15 transfer cases

[Nathan4400]

Hi everyone.

I own 2015 X6 50i and I'm having the same tugging sensation. And just like some other members removing the fuse gets rid of the issue.
My case is particular because I purchased the car used with the following tire setup:
Front: 275/45ZR20
Rear: 315/35R20
When I asked my dealership, they told me it is completely normal, however when I look up online it's always 40R for the front, never 45.
Could this be the culprit of my tugging sensation ? Please let me know if I should purchase new tires for the front.

[crystalworks]

That's a ~3.65% outer diameter difference. The transfer case is unhappy with anything > 1% from what I have read. I'd ask a tire shop. They'll know the factory tire sizes. Apparently better than the dealership.

[Nathan4400]

Originally Posted by crystalworks

That's a ~3.65% outer diameter difference. The transfer case is unhappy with anything > 1% from what I have read. I'd ask a tire shop. They'll know the factory tire sizes. Apparently better than the dealership.

Thank you for the feedback, I'll look into it with a tire shop.

[sergiyny]

Originally Posted by virtualbong

This is EXACTLY what is happening with my X5 after purchasing some used 22s. I started to feel this tugging at lower speeds during acceleration. I thought it was the lower links but what you guys have described seems to be exactly what is happening to me. My mechanic also thought it was my suspension so thankfully I have not replaced them yet.

How does one recalibrate the TC during an oil change? Do I just ask the dealership to do this since I normally bring it in to them to perform the oil change?

What tires sizes you purchased those 22s with?

[M302_imola]

Originally Posted by sergiyny

What tires sizes you purchased those 22s with?

I've had the best luck with 285/30/R22 front and 335/25/R22 rear.

[sergiyny]

Originally Posted by M302_imola

I've had the best luck with 285/30/R22 front and 335/25/R22 rear.

You should had zero issues with that setup. The difference is 0.5%

[M302_imola]

Originally Posted by sergiyny

You should had zero issues with that setup. The difference is 0.5%

Exactly!

[virtualbong]

Originally Posted by sergiyny

What tires sizes you purchased those 22s with?

shoot, I just changed them out to my winter setup but I suspect this is what is causing the hesitations. I didn't realize traction control would be impacted

[Jars914]

I would just like to thank everyone for this thread, i started experiencing a tugging/power loss upon acceleration, i changed the spark plugs and engine felt overall smoother but still had that tugging feeling. Was investigating and was praying it wasnt the transfer case, ended up just being my 22's and uneven tire wear. I put on my dedicated winters and cAr is driving smoother than ever.

[CMYACHTIE]

Originally Posted by Sophisticated Redneck

First, measure the circumference of your tires. Use a string or wire and wrap around the outside, if the front and back are off by more then one percent, recalibrating won't help for long as the ECU will continuously think the tires are slipping since they are not rotating the same speed and get caught in that loop of requesting new torque targets I mentioned above and that tugging sensation will come right back.

If circumference is within spec front to back, then call your dealer and ask as some will and some won't, mainly consider the TC as sealed unit and will not change or calibrate it, but they happily sell you a new one for 8 grand.....funny how that works.

You can also do it yourself with ISTA (what I used) and I have heard other members have been able to use the foxwell nt530 scanner with BMW software to do it also.

Otherwise call around an find a good independent mechanic that is familiar with the reset procedure and changing oil on BMW F15 transfer cases

Also can go to: willtheyfit.com, a lot easier….!! And enter your tire numbers.