2006 X3 - This thud, thump or clunk coming from rear is driving me crazy!!! Help!

[mongooz24]

My brothers and sisters in BMW crime:

I have a 2006 X3 3.0 (not sport). It currently has 85,000 miles on it and it had 74,000 miles when I bought it in May of 2009. It was already equipped with Pirelli Four Seasons P6 235/55 17 tires all around, they all match and have similar wear. The tires have about 30,000 miles on them.

Around the end of last year, I noticed that in parking lots or at low speeds, a strange thud, thump or clunk would come from the passenger side rear. Generally, it would happen around 5-10 mph, particularly as I let off the gas and make corners in a parking lot. Sometimes it seems like you can feel it in your feet when it happens, too and sometimes it seems harder or louder than other times. However!!! It's totally inconsistent, sometimes it happens and sometimes it does not, but it definitely happens only after being warm and driven for a bit. It never happens at higher speeds.

It's out of warranty, so I brought it to my independent repair guy who serviced my 540i from 110,000 to 180,000 miles when I finally sold it after twelve good years! They have a great reputation in town and I trust them. However, my fear is that they don't have a lot of X3 experience because many cars my year are just coming out of warranty or in extended warranty situations and have not shown up at his shop much yet.

First time I brought it in was Feb 2010, they replaced the transfer case mount. They thought it solved the problem because again, the noise is inconsistent. It did not solve it, so I brought it back a few weeks later. They kept it for almost two weeks, trying to get the problem to reoccur/test theories, etc. They finally repacked the bearing in the rear (they did this at no charge!!) and returned the car to me, thinking problem solved. He said they would have to be repacked regularly to keep the problem from returning.

THIS DID NOT SOLVE THE PROBLEM! I have been bewildered by the problem, but it doesn't seem to be "urgent," because it still doing it 7 months and 5,000 miles later. HOWEVER!!! It does seem to have gotten worse lately and is happening more frequently and seemingly with more force. Sometimes it feels like a tranny thing, but that was already "cleared," as a possibility.

I have seen in the forum about the wrong tires. From what I have been able to ascertain, my tires are approved for this car. Does anyone have any info to the contrary? (see tire description at the beginning of this thread)

Does anyone have any ideas? Unfortunately, my company closed last year and I am one of the numerous unemployed out there who can't find work and I can't afford to throw money at unsuccessful attempts to try and fix this. Even still, I have seen the posts on here of people with similar issues that have gone to dealers that seem to have no ideas either...

Any assistance would be greatly appreciated!

[Eric In Sac]

I have the same thing in my 2004. It may happen at higher speeds and I just can't hear it. It sounds to me like a rubber bushing has worn away so there is some play somewhere in the rear suspension or driveline. Just haven't really looked at it yet. In my old Z3, it was a worn bushing though.

[Rustynuts]

Just in case, I would change the fluid in your transfer case and rear Diff. The Diff can use any GOOD gear oil, Royal Purple, Amsoil, Redline, etc. But for the TC, I would go with the OEM even though it's not cheap ($50/qt) but you just need one bottle.

[JuansX3]

I got it. It’s the tires. I know it’s a bit late, but I have spent HOURS and days reading through thread after thread trying to find the fix to this problem. Like you, I wanted to make sure and not dump a ton of money on something that was not going to work. My issue matched the exact description given by mongooz24. The loud thud, thump and clunk were something I heard and felt every day. Sometimes even felt like something was going to fall off the bottom of the car. Slow turns in parking lots would sound like metal hammering onto metal and the thump would even cause me and my passengers to jerk in our seats.

After reading the many many different threads I found the popular diagnosis were: Transfer case, transmission, front thrust arm bushings and tires. I changed the front thrust arm bushings, per dealer’s instruction, and the problem did NOT go away. Since the other possibilities we very expensive, I decided to focus on the most cost effective option which was the tires. At the time I had 3 used pirellis on the car and 1 used goodyears that was bought at discount tire to replace a flat. All tires were the same size but had different wear and tear.

I spent the money to get 4 brand new pirellis, balance and alignment. The problem was fixed. I sometimes feel a very slight thud on my feet but it is not noticeable to anyone else in the car. Nothing like it was before. I was told this is simply part of how the car performs.

In one of the threads I read someone explained the sensitivity in BMW's and that a slight difference in the tires will produce "different tire speeds" and the car will try to adjust, which creates the thud, thump or clunk. I didn't understand it much at first, but brand new tires did the trick. Hope this helps someone. Cheers!

[6275benson]

Hi there thought I would share a similar experience.

I have a 2004 x5, I had some lock up on back brakes under extreme cornering and the 4 wheel drive light would light up on certain right hand corners only and I would get some vibration on the steering wheel. After many hours, exactly like your situation, 4 new tires & wheel alignment solved the problem.

With mine, wheel alignment was out with 1 back tire experiencing more wear, and the front tires different make and tread to rear tires, it would appear that the wheel sensors were picking up different wheel speeds on right hand bends and activating the ABS and the DSC would disengage in an effort to stabilise the car, hence the vibration and warning light.

I have a Bently service manual and in a few places it is recommended that the all the tires need to be identical.

[SupaWrench]

Same problem as Mongooz24 - he's described the problem perfectly. I've done the the following trying to solve it. Full flush trans service, changed rearend oil, Transasxle actuator gear, Transaxle mount, guibo disk, new rear shaft assembly, tires cuz I needed them anyway. I can tell you it ain't no tire problem. It's mechanical, something is loose in the rearend mounts or lash (play) in the ring and pinion gears. If you put the car on stands run the car put in drive and merely lift your foot off the brake it clunks like the rear assembly is going to drop from the car. Pretty cheesy if this is normal. My next attack is going to be focused there, but I can only do so much as this is my only transportation and need parts in hand before starting with a ONE DAY LIMIT on vehicle down time. A Discovery tear-down is out of the question at this point. Need a Yamaha R1 for parts running.

2007 BMW X3si
109,700 miles