[JCFans01]

Hey guys,

I have a transfer case issue on my 2019 X5 40i, like so many X5ers have. I'm in Toronto, Canada, and my original warranty just lapsed on Aug 31 2023. I purchased the extended warranty until Aug 31 2025. I don't drive often and my vehicle is still around the ~50,000KM (31,000 miles) mark. Keep in mind that in Canada, which I also just realized, the extended warranty is no longer being covered by BMW but by a third party-company who offers a VSC (Vehicle Service Contract) Platinum that cover pretty much the original warranty. BMW Canada used to cover their own extended warranty, but not anymore.

I started noticing shuddering when turning at low speed or at turning while gassing up. Brought it to the dealership and they diagnosed it as the transfer case being "worn out". They said they can replace under warranty but it's a CAD$14,000 job and for a repair like this VSC has to send a representative down to look at it and approve it. VSC took a look and said for them to approve it you must change the transfer case fluid first (not covered by warranty) and drive it 300KM. If the issue still persists, then they will approve the replacement. I paid CAD$340 for the fluid change.

I'm driving the first 100KM now and the issue seems to be totally gone. My question is:

1) Will the issue come back since they say my transfer case is "worn out".

2) Will I eventually have to replace the transfer case because it's "worn out".

3) Under regular use what is the life expectancy of a transfer case?

4) Considering it's "worn out" without actually knowing how worn out it is, when do I have to replace it?

5) The dealership says if the issue persists, bring it back and they'll do the replacement without needing VSC in-person approval because they've already come down and saw the car. Does this mean at the slightest shudder I can just bring the car in and BMW will just replace the transfer case?

6) Is there any way I can argue under SI-B27-02-20 (https://www.tsbsearch.com/BMW/SI-B27-02-20) that BMW should cover the transfer case fluid change?

Thank you in advance for your input.

[Giggler]

I’m curious what is the mileage interval BMW recommends for transfer box fluid replacement/flush. It seems to be that they don’t recommend it at all, seems like you got your first one at 30k miles, which to me is nonsense. There are so many components to an AWD drivetrain that there could be any number of things causing early failures.

1. Staggered wheel setup prevents tire rotation, potentially causing tire wear differences and overall tire diameter differences between front and back. I have read that BMW recommends no more than 2mm variance between front and rear tire diameter to prevent premature transfer box wear. As it is known, Xdrive is RWD biased, and folks who drive aggressively could EASILY put 2mm wear on the rears before the front. People who live in the city could wear the front tires prematurely due to all the turning.


2. Full throttle at low speed, or cornering at high speed wearing out clutch pack, stressing the gears, overheating the fluid thus degrading the performance of the fluid. Aggressive drivers should flush their fluid yearly, but who knows what BMW recommends?

3. Under-inflated rear tires while carrying heavy loads in the back or towing. One single under-inflated tire causing a drivetrain imbalance.

4. Drive shaft, driveline issues: possible loose connection points at bolted intersections along the driveline connecting to the transfer box and/or poorly lubricated shaft due to lack of maintenance and environmental conditions.

5. Potential for water to get inside the transfer box via the vent due to driving in wet weather, high water, or even possible repeated condensation cycles due to parking outside all year.

These are all the reasons I could think of that could prematurely wear a transfer box. It’s not clear to me however if BMW has engineered something that is prone to failure or if people are stressing out their drivetrains due to driving style or the harsh environmental conditions they drive in.

[rmorin1249]

Absolutely inexcusable that any transfer case "wears" out in less than 50k miles. I've owned several AWD vehicles
that have gone 100k miles without any drive line issues.

And this water intrusion issue is pure BS. Who doesn't drive in the rain and through puddles of water? Shame on BMW.

[eelnoraa]

100k?? How about 250k miles. Awd in this kind of cars get very light use. But in my limited experiences with awd, binding will happen at fluid degrade. Changing out fluid could resolve the issue. This is with my evo8 at 150k, and crv at 230k. I still have tha cvr now at 250k. At 31k miles, even fluid change seems too early

[Giggler]

Originally Posted by rmorin1249

Absolutely inexcusable that any transfer case "wears" out in less than 50k miles. I've owned several AWD vehicles
that have gone 100k miles without any drive line issues.

And this water intrusion issue is pure BS. Who doesn't drive in the rain and through puddles of water? Shame on BMW.

Yes, everyone drives in the rain at some point, but maybe if you’re commuting 70+mph on the highway during a heavy downpour on a regular basis because you live in a rainy climate like the Pacific Northwest, you might be slowly introducing moisture into your transfer box in small increments until it finally becomes a problem. Completely hypothetical, but water has to get in somehow.

This issue is apparently very common with Porsche due to a poorly located vent (edit: I think there’s even a class action on the matter) and there’s a recommended aftermarket fix to add 1 to 2oz of Ford XL-3 Friction Modifier. If I were out of warranty and my transfer case was starting to shutter, I wouldn’t hesitate for a second to include 1oz of this additive in my fluid replacement before potentially shelling out thousands on a new TC.

[JCFans01]

A quick update here:

So I have driven past the 300km requirement after the fluid change (1000km to be exact) and the issue is still there. Granted, it has MUCH improved but still there. Here is a timeline of updates.

Oct 5 - at dealership and BMW technician confirmed issue persists
Oct 6 - warranty company adjuster did a road test confirmation
Oct 9 - CA Thanksgiving
Oct 11 - warranty paperwork approval expected
Oct 12 - transfer case part needs to be shipped from Vancouver
Oct 19-20- transfer case repair 2 days expected

Should have a brand new transfer case by Oct 21. Fingers crossed!

[CGG]

Thanks for the update. Makes me think I should get the extended warranty if I keep the my 21 x540i ......

[JCFans01]

Quick question: I have read about cases where the dash needs to be replaced and the work is never nearly as good as the original factory work.

With a transfer case replacement, do I have to worry about the work being done never as good as the factory work as well?

Thank you.

[rmorin1249]

If I start hearing any similar noises I will trade immediately. Already decided this is probably my last BMW.

[Marty in NY]

Originally Posted by JCFans01

Quick question: I have read about cases where the dash needs to be replaced and the work is never nearly as good as the original factory work.

With a transfer case replacement, do I have to worry about the work being done never as good as the factory work as well?

Thank you.

I don't believe you have to worry about it, its a pretty simply procedure and all done under the car, as easy as abc, 123, all mechanical, just a remove and replace, bolt for bolt job. I had it done on my former X3, IIRC, three or four bolts and it was out.

[JCFans01]

Originally Posted by Marty in NY

I don't believe you have to worry about it, its a pretty simply procedure and all done under the car, as easy as abc, 123, all mechanical, just a remove and replace, bolt for bolt job. I had it done on my former X3, IIRC, three or four bolts and it was out.

My dealership led me to believe that’s its a complex job, many parts are connected to the transfer case and it would take 2 full days.

[F15_SGM]

Originally Posted by JCFans01

My dealership led me to believe that’s its a complex job, many parts are connected to the transfer case and it would take 2 full days.

It's just an electronic box with fluid. I think you just unbolt the drive shaft and unbolt it and disconnect the plug. Mine was swapped and car feels exactly new nothing is changed in terms of feel or noise quality.

[Marty in NY]

Originally Posted by JCFans01

My dealership led me to believe that’s its a complex job, many parts are connected to the transfer case and it would take 2 full days.

My dealership did the replacement in just a few hours.

[eelnoraa]

Originally Posted by F15_SGM

It's just an electronic box with fluid. I think you just unbolt the drive shaft and unbolt it and disconnect the plug. Mine was swapped and car feels exactly new nothing is changed in terms of feel or noise quality.

Maybe not as simple as you said. I think the xfer case is bolt to the transmission case. There are two drive shafts, to the front and to the rear. So first need take off the mounting bracket, which looks to be a steel cross member kind of things, then need to put in proper support, disconnect both drive shafts, the unbolt transfer case from transmission. From under carriage looks, I wonder if exhaust pipe is in the way, if so, may need to drop that as well. I think 2 day is for sure excessive, but 2 hours seems optimistic to me too

[streborx]

Originally Posted by Marty in NY

My dealership did the replacement in just a few hours.

More and more dealerships are scheduling service appointments for their convenience rather than yours. Leave the car there for 2 days so they can work on it when a qualified tech is available. This keeps their service bay full and all their techs busy while a queue of cars line up in the car park.

[LOFT]

To deal with my own ignorance on this subject I "googled" BWM transfer case. Some interesting highlights:
- Manufactured by Magna (who is a leading parts manufacturer so it's not junk)
- Supposed to last well past 100k miles
- Replacements are low-mid $000, not double digit $000

Leads me to conclude that if I want to keep my BMW post-warranty, I would look for a good non-BMW shop to hand the mechanical bits such as this issue.

Good luck to fellow Torontonian JCFans01 who is dealing with this.

[JCFans01]

Originally Posted by LOFT

To deal with my own ignorance on this subject I "googled" BWM transfer case. Some interesting highlights:
- Manufactured by Magna (who is a leading parts manufacturer so it's not junk)
- Supposed to last well past 100k miles
- Replaces are low-mid $$$, not double digit

Leads me to conclude that if I want to keep my BMW post-warranty, I would look for a good non-BMW shop to hand the mechanical bits such as this issue.

Good luck to fellow Torontonian JCFans01 who is dealing with this.

To be fair I did ask around to highly regarded shops who service Europeans cars, including ones I had frequented to bring my out-of-warranty BMWs in the past. They flat out said they don’t do transfer case replacements. I called 3 shops, for data point purposes.

[streborx]

Originally Posted by Giggler

IÂ’m curious what is the mileage interval BMW recommends for transfer box fluid replacement/flush. It seems to be that they donÂ’t recommend it at all, seems like you got your first one at 30k miles, which to me is nonsense. There are so many components to an AWD drivetrain that there could be any number of things causing early failures.

1. Staggered wheel setup prevents tire rotation, potentially causing tire wear differences and overall tire diameter differences between front and back. I have read that BMW recommends no more than 2mm variance between front and rear tire diameter to prevent premature transfer box wear. As it is known, Xdrive is RWD biased, and folks who drive aggressively could EASILY put 2mm wear on the rears before the front. People who live in the city could wear the front tires prematurely due to all the turning.


2. Full throttle at low speed, or cornering at high speed wearing out clutch pack, stressing the gears, overheating the fluid thus degrading the performance of the fluid. Aggressive drivers should flush their fluid yearly, but who knows what BMW recommends?

3. Under-inflated rear tires while carrying heavy loads in the back or towing. One single under-inflated tire causing a drivetrain imbalance.

4. Drive shaft, driveline issues: possible loose connection points at bolted intersections along the driveline connecting to the transfer box and/or poorly lubricated shaft due to lack of maintenance and environmental conditions.

5. Potential for water to get inside the transfer box via the vent due to driving in wet weather, high water, or even possible repeated condensation cycles due to parking outside all year.

These are all the reasons I could think of that could prematurely wear a transfer box. ItÂ’s not clear to me however if BMW has engineered something that is prone to failure or if people are stressing out their drivetrains due to driving style or the harsh environmental conditions they drive in.

You make several excellent points regarding transfer case damage, and IMO, your point #1 is the most interesting and probable (which is why it's at the top, I'm sure).

BMW isn't the only manufacturer whose transfer cases are susceptible to damage. Other AWD brands that use similar transfer case designs also experience failure, and it seems mostly a consequence of mismatched wheel diameter/circumference. What's annoying about BMW is that its staggered wheel setups with short treadlife tires and an inability to rotate them to even out the wear seem to exacerbate the likelihood of mismatch and lead to transfer case problems.

I've read similar information regarding a maximum acceptable 2mm diameter difference, front versus rear. 2mm is 3/32", and seemingly not much, but the staggered set of Conti's that came on my X7 have an 8/32" tread to begin with, and everyone agrees that 2/32" is end of life. So 6/32" is the life of the tire, and some owners report toasting them in as little as 12K miles. A tire that sheds tread that quickly can probably be relied on to do so differentially front to rear, and be exceptionally sensitive to balance, alignment and pressure.

If you experience irreparable road damage to a half worn run flat, mounting a new 8/32" tread with 3 others at 5/32" seems like assaulting your transfer case with a crowbar. Replacing a full set of run flats with 10K miles (or less) on them at a cost of about $2K isn't in everyone's budget. At $4/gallon, that's as much in fuel as it took to drive the 10K miles!

I've seen other forum posts by folks who want to up-size their wheels or change tire brands, but can't match up the same tire dimensions as OEM, and ask if half an inch difference between front and rear is going to be a problem. The answer is not until your transfer case screams in agony before falling out in pieces.

I changed out my OEM runflats (275/40R22 front & 315/35R22 rear) and squared up with a set of 275/50R20's, which keeps front and back diameters identical and changes the diameter/circumference by only +0.3%. Most important, these Michelins are rated with 60K treadwear, and I can rotate the tires every 5K to even out the wear. Others might disagree, but I believe this is a better configuration than OEM as far as the transfer case health goes. I check the tread depth and wear every couple thousand miles, and monitor the pressure almost every time I drive.

Buy a digital tread depth gauge and keep an eye on your tires. If you're OCD, buy a 10 ft. cloth tape measure and measure the tire circumferences too. Don't deviate from OE tire dimensions, or stay close with a square up. Tire specs are more important than how they look.

[eelnoraa]

Let’s me relistic, 2mm allowance difference between front and rear is for sure misinformation. The nominal overall diameter of x5 is 30”, or 762mm. 2mm represents 0.2%, it is noise. Even if tire pressure is off by 1-2 psi, the change in diameter is that. Plus the front will always rotate faster than rest unless the car is going 100% straight, any slight bank on highway, the front will rotate faster by 0.2%. Different tire wear pattern cannot and should not be the cause of transfer case damage.

[tooloud10]

I assume that “worn out” is just a clumsy description for a failed transfer case.

[AGONXF30]

Originally Posted by eelnoraa

Let’s me relistic, 2mm allowance difference between front and rear is for sure misinformation. The nominal overall diameter of x5 is 30”, or 762mm. 2mm represents 0.2%, it is noise. Even if tire pressure is off by 1-2 psi, the change in diameter is that. Plus the front will always rotate faster than rest unless the car is going 100% straight, any slight bank on highway, the front will rotate faster by 0.2%. Different tire wear pattern cannot and should not be the cause of transfer case damage.

That 2mm needs to be seen in writing by BMW and not some forum bubba!

Subaru has also done RWD biased AWD systems, which are also subsebtible to tire diameter, but they do not fail at 30K.

[streborx]

Originally Posted by AGONXF30

That 2mm needs to be seen in writing by BMW and not some forum bubba!

Subaru has also done RWD biased AWD systems, which are also subsebtible to tire diameter, but they do not fail at 30K.

C'mon -- let's play nice. No need for name calling.