[StNik]

Hi All,

My BMW X3 (150,000 Miles, 2005, E83 2.5L, 5-Speed Automatic) recently started making a low rumbling noise (about 180hz sine) and low vibration while cruising steadily at 40mph or faster. The vibration can be felt on the center armrest, and seems to emanate from the center or the back of the car. The vibration is present when holding the speed steady at 40mph or higher speeds, or when accelerating. I think vibration is present at lower speeds but is more difficult to detect. It's present in Automatic mode, Sport, or Manual Steptronic mode, and detectable mostly in 3rd,4th, and 5th gears.

While cruising at 40mph, the vibration/noise stops immediately if I take my foot off the gas pedal or put the car into Neutral. While coasting in Neutral, revving the engine doesn't reproduce the vibration/noise.

The engine runs smooth as silk, and the car is not throwing any error codes when scanned. The gear shifts are fine. There is no other noise or issue.

These cars tend to have similar problems around the same miles/years, so I was wondering if anyone has experienced this issue and knows the root of the vibration/noise?

Thanks for your help !

[jeddo45]

Originally Posted by StNik

Hi All,

My BMW X3 (150,000 Miles, 2005, E83 2.5L, 5-Speed Automatic) recently started making a low rumbling noise (about 180hz sine) and low vibration while cruising steadily at 40mph or faster. The vibration can be felt on the center armrest, and seems to emanate from the center or the back of the car. The vibration is present when holding the speed steady at 40mph or higher speeds, or when accelerating. I think vibration is present at lower speeds but is more difficult to detect. It's present in Automatic mode, Sport, or Manual Steptronic mode, and detectable mostly in 3rd,4th, and 5th gears.

While cruising at 40mph, the vibration/noise stops immediately if I take my foot off the gas pedal or put the car into Neutral. While coasting in Neutral, revving the engine doesn't reproduce the vibration/noise.

The engine runs smooth as silk, and the car is not throwing any error codes when scanned. The gear shifts are fine. There's is no other noise or issue.

These cars tend to have similar problems around the same miles/years, so I was wondering if anyone has experienced this issue and knows the root of the vibration/noise?

Thanks for your help !

I have something similar in ours. I'm guessing maybe transfer case related maybe? Hoping it's not a crazy expensive fix...

[Askur44]

I think it's your carrier bearing. Go down there and try and wiggle the drive shaft. See if the the carrier bearing is shot. You should also check the ujoint that's there as well. Good luck

[StNik]

Thanks for the great suggestions and helpful videos guys. One thing we can rule out is tires, balance, and alignment. Installed new tires (it was time), excellent balance and alignment. But the vibration at 40 is still there...it does seem to start around 30mph

I loved the math video as I'm a math nerd and had measured the vibration at 25hz. I'll retest given the new tires and use the new app you suggested to take a better measurement.

I'll also get under the car and check carrier bearing, ujoint, or anything loose.

Thanks again, will keep you posted.

[StNik]

I checked all the driveshafts, carrier bearing, ujoint, guibo, and anything else I could get my hands on and everything was solid, no wiggle.

Also disconnected the transfer case wires, which I think disables the transfer case (?) but the vibration was still present at 40mph and accelerating or holding steady.

Vibration measured at 39hz at 45mph and seems to be coming from the center middle of the car. I might need to disassemble the driveshaft and check each component.

Could the torque converter be causing the issue?

[englishtom1596]

torque converter wouldn't cause a vibration. Most likely something driveshaft related. Also check your transmission mount isn't shot as this will cause misalignment of the driveshaft.

[StNik]

The problem is solved. But I still can't believe it. The car runs smoothly and quietly, like new.

I couldn't find any drive train issues as expected, and didn't replace any parts.....that I know of.

But, on a whim, after filling-up the other day, I added a small bottle of STP Fuel Injector Cleaner to the fuel tank. First time ever. Two days later the vibration is gone. Car is like new. Either the STP fixed something or my wife secretly took the car in for repairs before I got in over my head on this issue LOL :-)

[englishtom1596]

I think that may just be coincidence.. but hey, if the vibration stopped who cares lol

[F30NFifty5]

Originally Posted by StNik

The problem is solved. But I still can't believe it. The car runs smoothly and quietly, like new.

I couldn't find any drive train issues as expected, and didn't replace any parts.....that I know of.

But, on a whim, after filling-up the other day, I added a small bottle of STP Fuel Injector Cleaner to the fuel tank. First time ever. Two days later the vibration is gone. Car is like new. Either the STP fixed something or my wife secretly took the car in for repairs before I got in over my head on this issue LOL :-)

When I changed my transfer case gear, I left 2/4 13mm bolts for the subframe brace a little lose and I got a pretty wicked vibration. Check those 4 bolts if the vibration comes back. Think I'll try some of that STP Fuel Injector Cleaner as well just for sh*ts and giggles.

[murtrub@aol.com]

Feeling my way around!
Thx