Thumping Sound, Kick, Deceleration Jerk
 

I've been experiencing a few annoying issues on a recently purchased 2005 X5 4.4i. Wondering if anyone has solved them.

1. There seems to be a rotational thumping sound when accelerating at highway speeds. It sounds like its coming from the rear.

2. When slowing down and then accelerating there is sometimes this loud thud and a kick.

3. When coming to a stop, it seems as if the car cannot stop smoothly. Even when depressing the brake pedal slowly the car always seems to hesitate or jerk at the end.

A quick inspection under and around the car didn't reveal anything out of the ordinary. :dunno:

1 and 2 sound related and could be the rear prop shaft cv joint, at the front of the rear diff.

3 seems to be a feature of the X5. I find it incredibly hard to stop without a small "jerk", especially since my gearbox 2-1 slam dictates a certain stopping technique, at odds with a smooth stop.

The jerk was lessened a lot when I replaced the front control arm bushes - they were shot and actually clunked if you tapped the brakes suddenly.

Not sure how much it relates, but I have a 2-1 thud that sucks and other times coming to a stop in 2nd it will thud. I've had to resort to manny shift to avoid my 2-1 thud. Only way I can control it. You could also check the Guibo as those can lead to some of the symptoms you've described.

Make sure your thrust bushings are ok. The front wheels will move nearly 2cm when you hit the brakes when the bushings are when worn


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I'll have to take a look at that. And the front control arm/thrust bushings have been replaced because I was experiencing that clunk. It solved that issue but the others remained.

The guibo looked intact, is this something that needs to be removed to fully inspect it?

Control arm/thrust bushings were replaced and it did solve the clunk that I originally thought was a sticky caliper. I guess the issues I'm experiencing are less common than I thought. Waiting for a nice day for further inspection.

Lots of what you described sounds like subframe bushings. Especially freeway thump from the rear.

Example: a distinct thump if on power up hill and hit a bridge expansion bump. Every time I'll get a thump that feels like a gear slipping a tooth. E.g. Instantly loose power and get it back.

The twist of the subframe does exactly that: for a split second when the car gets light on the spring power goes to twisting the subframe not pushing the car forward.

I also get a creak every time I start accelerating from zero as the subframe twists.


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How many miles are on the truck? If over 100,000 then it's likely a driveshaft servicing is in order. I did both guibos and my CSB as well as greasing the splines on the shafts. Solved some noise issues I was having.

Note: your clunk sounds more like a rear bushing, just suggesting the above as part of maintenance.

@ crystal: does CSB sound like a wheel bearing if it fails? My wife's x5 sounds like a wheel bearing going but I can't confirm the corner. I did replace 3/4 of her bearings so I'll be replacing the last one soon but from your suggestion is due for some drive maintenance


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^CSB usually manifests as a drive train judder at first under acceleration, first only under hard acceleration but as it gets worse even light pedal will cause it. Then as it gets worse it will start knocking or clunking, getting faster as accelerating because the driveshaft is wobbling.

I've never heard bearing whine/groan from the CSB, but that might just be I've never noticed it until the physical judder and thudding starts. :dunno:

I think if your last bearing doesn't cure it I'd start listening to the diffs to see if they are making the noise.

It seems it's not usually the bearing itself that fails but rather the rubber suspension supporting the bearing. Online photos show many instances of the rubber torn from the bracket....

http://www.foreignaffairs.us/gallery...1/DSCF0007.jpg