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Discussion Starter #1
Hey guys, great to be back. I posted about this maybe a year or so ago with a video, but no one was able to differentiate the sound over the music in the car. I've gathered together a few clips over the past several months hoping that they're better than the last. This happens as the car shifts gears whenever I accelerate with low to mid throttle. It also happens while accelerating after manually shifting from 1st to 2nd. Completing left turns just about always produces this sound. The only way to stop this embarrassing noise from happening is to either be a leadfoot off the line or let off the gas just before the car should shift gears, which takes proper timing, and leave it off for a second or two before gassing it again. The tires were changed just before this started. Could the problem be with the tires themselves or something deeper?

https://youtu.be/HwdkyCRpiRY

Who wants bet this is why that red truck pulled over?
 

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Does it sound like tire rubbing in real?

What are the tire sizes? are they any different than the previous setup?

Any tread size difference front and rear?
 

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Could be many things, and without being there in person hearing it, feeling the vibrations, etc., it's tough to say.

But one easy thing to look for is something like a loose exhaust system rubbing up against a driveshaft.
 

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Could be many things, and without being there in person hearing it, feeling the vibrations, etc., it's tough to say.

But one easy thing to look for is something like a loose exhaust system rubbing up against a driveshaft.
agree. I don't think it's the tires. my bet is on the transfer case that's why I asked wheel sizes.
 

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Discussion Starter #5
Does it sound like tire rubbing in real?

What are the tire sizes? are they any different than the previous setup?

Any tread size difference front and rear?
Woah, I never received any notifications so I had no idea I had gotten any replies.

Yes the tires are the same size as the previous setup. It sounds just like it does in the video and there are no vibrations or anything. I really don't feel anything when it happens. Does that change anything?
 

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Woah, I never received any notifications so I had no idea I had gotten any replies.

Yes the tires are the same size as the previous setup. It sounds just like it does in the video and there are no vibrations or anything. I really don't feel anything when it happens. Does that change anything?
Disconnect the electrical connector of the transfer case module. This way the car becomes a rear wheel drive car. If the sound disappears, it's gonna be the transfer case.

A70006 on the picture below

 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 100K miles NOKIAN WR G3 20K miles
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Consult your owner's manual. DSC and DTC are deactivated by a sustained press of their OFF selector button.
 

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Discussion Starter #8 (Edited)
Thanks for the replies. I was going to try disconnecting the module when I had the chance, but it looks like I don't need to. Turns out it actually was the transfer case, among many other things. Firestone took care of a flat for me and told me the rear tires may be misaligned, so I decided to bring up the noise. They did a scan and pulled up these codes: 52D4VTG (incremental transducer), 5463VTG (mechanism faulty), 5462VTG (servomotor or coupling force too high), 55C4 (no message from DSC), 27CC DME (DMTL leakage), 5F3A DSC (transfer case malfunction). The rear differential mount is also cracked. Does anyone know what exactly these mean? Are these all related to the same problem? Or is this going to be a series of repairs?

Could any of these be related to the BRAKE, ABS, & 4X4 lights that came on over the summer? This noise has been occurring for 1-2 years, but these lights came on only a couple of months ago. I also had the SES light come on shortly after and pulled up this code yesterday with my scanner: P0442 (evaporative emission system leak detected). Is that related to the DMTL leakage or is that a separate issue entirely for another thread?

I don't plan on servicing the car anytime soon since I just had all four tires changed, but I'd like to at least get to the bottom of it.
 

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Thanks for the replies. I was going to try disconnecting the module when I had the chance, but it looks like I don't need to. Turns out it actually was the transfer case, among many other things. Firestone took care ...
1. "rear tires may be misaligned"
This is either worn out bushings on suspension parts or Firestone isn't familiar with BMW setup that uses larger negative camber in the rear than other cars making the inner edge wear out faster.
Since you have new tires it makes sense to double check this.

2. SES & P0442 & DMTL
these are the same thing and related to the fuel tank ventilation system. Doesn't cause drivability issues but will fail a smog check.

3. BRAKE, ABS, 4X4 lights / VTG errors
VTG is the control module for the transfer case. VTG, DSC modules are working together, one can influence the others. All these errors might clear up once you fix the VTG but I can't tell if there is any other issues as well.

4. rear differential mount is cracked
not sure how bad that is. Not very common failure. I'm wondering if this could affect the transfer case. unlikely but not impossible. Make sure this gets fixed when you pull the trigger on the transfer case. If the crack is really bad and the diff is really loose, might be the cause for that weird sound.
If you want to diagnose it yourself, put a GoPro there and see how much the diff moves when accelerating hard.
 

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Discussion Starter #10
1. "rear tires may be misaligned"
This is either worn out bushings on suspension parts or Firestone isn't familiar with BMW setup that uses larger negative camber in the rear than other cars making the inner edge wear out faster.
Since you have new tires it makes sense to double check this.

Ah, makes sense. At least I don't have to worry about that too!

2. SES & P0442 & DMTL
these are the same thing and related to the fuel tank ventilation system. Doesn't cause drivability issues but will fail a smog check.

So that's another issue then.

3. BRAKE, ABS, 4X4 lights / VTG errors
VTG is the control module for the transfer case. VTG, DSC modules are working together, one can influence the others. All these errors might clear up once you fix the VTG but I can't tell if there is any other issues as well.

Could this mean they just failed a couple of months ago and are not likely the cause of the noise?

4. rear differential mount is cracked
not sure how bad that is. Not very common failure. I'm wondering if this could affect the transfer case. unlikely but not impossible.

What about the VTG & DSC rather than just the transfer case?

Make sure this gets fixed when you pull the trigger on the transfer case. If the crack is really bad and the diff is really loose, might be the cause for that weird sound.
If you want to diagnose it yourself, put a GoPro there and see how much the diff moves when accelerating hard.
I'll try this as soon as I figure out where the rear diff is.
 

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I'll try this as soon as I figure out where the rear diff is.
here is a video for a differential with good mounts, see it barely moves.
https://www.youtube.com/watch?v=kZjy5gNHu94

"Could this mean they just failed a couple of months ago and are not likely the cause of the noise?"

if the diff moves a lot under acceleration then that would be my first suspect for the weird noise

"4. rear differential mount is cracked
not sure how bad that is. Not very common failure. I'm wondering if this could affect the transfer case. unlikely but not impossible. "

"What about the VTG & DSC rather than just the transfer case?"


Loose differential would mechanically stress the transfer case. Wouldn't really affect the VTG itself.

VTG failure is quite common and can be unrelated to the differential.
"servomotor or coupling force too high" makes me think something is seized in the transfer case or the motor is giving up. If your diff is not loose, then the sound is coming from inside the transfer case.

here are some documents about the system:

ftp://cpe-98-148-219-26.socal.res.r...s/ST036 X5 Complete Vehicle/10_xDrive_DSC.pdf

http://share.qclt.com/bmw资料/1102_Driving Dynamic Systems/English/Participant_manual/E83 xDrive.pdf
 

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Rear differential is the rear gear, and is what the rear driveshaft connects into. May need to remove the spare tire carrier to really get a good look. If that is cracked, that would be number one on my book to fix. It may not need a replacement, I'd get in there with a welder to glue it back together first.
 

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It may not need a replacement, I'd get in there with a welder to glue it back together first.
"The rear differential mount is also cracked."

I expect that it's the rubber bushing that's cracked and not the metal frame. So it's "easy" to replace.
 

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I put my dashcam underneath the car right where I think the rear diff is. I'm not sure if this is the right way to do it or if I'm even on target, but I do see some movement.
the differential is in the lower right corner of your video. But nothing is loading the diff there.

you need to put some load on the diff in order to see if it moves.

option 1: not sure if your electronics let you do it (easy to do it with a manual transmission) // not very much recommended with an automatic
put down the GoPro on the ground facing the diff, (the way you did it already) push the brakes, put the car in D or 1st gear and step on the gas !gently! and release it immediately but keep the brakes pressed for the entire time and the car should not move

option 2: you mount the GoPro onto the car and watch the differential while driving and under heavy acceleration. Just like the video I posted.
 

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Option #1 is how I burned through a set of tires in an afternoon in high school. ******** like the smell of burning rubber. not really an option in an AWD car. Option number 1 is also how I free up frozen u joints when pulling old driveshafts.
 

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To me it sounds exhaust related...when the motor hits that certain harmonic it vibrates...check your cats and make sure there not coming apart inside or a baffle in the muffler broke loose

Sent from my LG-H901 using Tapatalk
 

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Discussion Starter #19 (Edited)
Finally figured out a way to fix my dashcam underneath the car without risking losing it and took a 5 minute drive around the neighborhood. I taped it to a tube-like structure just inside of the left rear tire.

https://youtu.be/fFpNUie75QQ

You can hear that dreaded noise at around 1:56 and 3:32. That whirring noise from 2:20 onward is most likely the tire rubbing up against the power cord for the camera. It must have come loose from where I secured it. I could hear it from inside the car at low speeds and knew what was up. Back to the differential, I really don't think that movement is normal, but what do I know?

Also, regarding the transfer case/4X4 issue, it's started raining here and the car's tires slip quite a bit more than I remember with just moderate driving. It feels like the car is RWD now. Does an issue with the transfer case or whatever is causing those symbols mentioned earlier tend to knock out AWD and/or traction control? Normally I'm confident with the car in the rain, not so much anymore.
Edit: Also looks like ABS is out the window as well. Never thought that ABS & 4X4 had actually stopped doing their job when they lit up. This increases the urgency to deal with this. If only I had the monies.

Hopefully the info in this post is helpful. Thanks for the responses so far. :thumbup:
 
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