Help Me Diagnose a Bad Rear CV Axle

rothwem · 11-11-2019, 08:33 AM

I've got a RWD E91, automatic transmission. I've owned the car for about 7 months now, and since I got it, I've had a light vibration on very hard acceleration. Google tells me its possibly the torque converter, but it hasn't gotten worse so I've ignored it and I don't really have an opportunity to accelerate at the rate that causes the issue very often.

Lately though, I've been having a little noise that occurs under light acceleration after the car is warmed up. It sounds sort of like a woodpecker, and is faster in frequency with increasing speed. Its louder when the suspension is loaded up in the rear also. Letting off of the gas makes the sound go away. The sound is coming from the driver's rear corner of the car, and its pretty faint.

So, with the acceleration vibration and the new noise, I'm kinda thinking its one of the CV axles. Any thoughts about how to diagnose on jackstands? CVs always have a bit of rotational play in my experience, so how do I figure out if its bad enough to make noise on the car?

1275 · 11-12-2019, 06:28 AM

I recently replaced the rear left hand axle of my 08 e91 335i (RWD) due to very similar symptoms, which I also assumed to be a failed CV joint. Visually the inner CV joint appeared fine, other than a very light film of grease and dirt. The replacement axle has fixed the issue completely.

I am not sure if it was the inner CV or something else that had failed, so figured a new axle was the best plan of attack.

While diagnosing the problem, I found simply jacking up the rear of my car would make the noise go away for several days.( the joke was on me after the first miracle fix made the sound go away for a week... simply by swapping tyres left to right). I also found the noise only occurred when the engine was under load, with light acceleration from a stop, or around 80kmh resulting in the loudest sound. If it didn't go away, it would sound like a faint, rolling drumming noise at 100kmh but a classic busted CV joint at slow speeds turning right. Again, mine was very much intermittent so could easily go away for a week or more.

I note it isn't a noise like the "cow bell" sound on so many utube videos.

Hope this helps.

rothwem · 11-12-2019, 08:08 AM

Quote:

Originally Posted by 1275

I recently replaced the rear left hand axle of my 08 e91 335i (RWD) due to very similar symptoms, which I also assumed to be a failed CV joint. Visually the inner CV joint appeared fine, other than a very light film of grease and dirt. The replacement axle has fixed the issue completely.

I am not sure if it was the inner CV or something else that had failed, so figured a new axle was the best plan of attack.

While diagnosing the problem, I found simply jacking up the rear of my car would make the noise go away for several days.( the joke was on me after the first miracle fix made the sound go away for a week... simply by swapping tyres left to right). I also found the noise only occurred when the engine was under load, with light acceleration from a stop, or around 80kmh resulting in the loudest sound. If it didn't go away, it would sound like a faint, rolling drumming noise at 100kmh but a classic busted CV joint at slow speeds turning right. Again, mine was very much intermittent so could easily go away for a week or more.

I note it isn't a noise like the "cow bell" sound on so many utube videos.

Hope this helps.

Ha! Okay awesome. The sound literally sounds just like a woodpecker, I'm not sure if you have those in Austrailia, but its sort of a hollow clicking/popping sound several times per second. Not cowbell-like at all.

1275 · 11-22-2019, 12:27 AM

Sorry for the late reply.

So it turns out there are a lot of woodpecker videos on Youtube! I don't think too many Woodpeckers make it this far south...

I would say that's a great description of the sound. The tone does seem to change depending on the speed, but once on the highway that was the sound I was hearing.

To confirm it's now been about 5 weeks since I changed the axle and the noise has not returned. I haven't taken apart the old shaft/CV to confirm, but I don't know if I would be able to see anything different.

Good luck and let us know how you go!

11-11-2019, 08:33 AM	#1
rothwem Major 475 Rep 1,191 Posts Drives: 2009 BMW 328i Wagon Join Date: Apr 2009 Location: Asheville, NC iTrader: (0) Garage List 2009 BMW 328i [0.00]	Help Me Diagnose a Bad Rear CV Axle I've got a RWD E91, automatic transmission. I've owned the car for about 7 months now, and since I got it, I've had a light vibration on very hard acceleration. Google tells me its possibly the torque converter, but it hasn't gotten worse so I've ignored it and I don't really have an opportunity to accelerate at the rate that causes the issue very often. Lately though, I've been having a little noise that occurs under light acceleration after the car is warmed up. It sounds sort of like a woodpecker, and is faster in frequency with increasing speed. Its louder when the suspension is loaded up in the rear also. Letting off of the gas makes the sound go away. The sound is coming from the driver's rear corner of the car, and its pretty faint. So, with the acceleration vibration and the new noise, I'm kinda thinking its one of the CV axles. Any thoughts about how to diagnose on jackstands? CVs always have a bit of rotational play in my experience, so how do I figure out if its bad enough to make noise on the car?
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11-12-2019, 06:28 AM	#2
1275 Private First Class 63 Rep 137 Posts Drives: 335i Touring Join Date: Feb 2016 Location: Australia iTrader: (0)	I recently replaced the rear left hand axle of my 08 e91 335i (RWD) due to very similar symptoms, which I also assumed to be a failed CV joint. Visually the inner CV joint appeared fine, other than a very light film of grease and dirt. The replacement axle has fixed the issue completely. I am not sure if it was the inner CV or something else that had failed, so figured a new axle was the best plan of attack. While diagnosing the problem, I found simply jacking up the rear of my car would make the noise go away for several days.( the joke was on me after the first miracle fix made the sound go away for a week... simply by swapping tyres left to right). I also found the noise only occurred when the engine was under load, with light acceleration from a stop, or around 80kmh resulting in the loudest sound. If it didn't go away, it would sound like a faint, rolling drumming noise at 100kmh but a classic busted CV joint at slow speeds turning right. Again, mine was very much intermittent so could easily go away for a week or more. I note it isn't a noise like the "cow bell" sound on so many utube videos. Hope this helps.
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11-22-2019, 12:27 AM	#4
1275 Private First Class 63 Rep 137 Posts Drives: 335i Touring Join Date: Feb 2016 Location: Australia iTrader: (0)	Sorry for the late reply. So it turns out there are a lot of woodpecker videos on Youtube! I don't think too many Woodpeckers make it this far south... I would say that's a great description of the sound. The tone does seem to change depending on the speed, but once on the highway that was the sound I was hearing. To confirm it's now been about 5 weeks since I changed the axle and the noise has not returned. I haven't taken apart the old shaft/CV to confirm, but I don't know if I would be able to see anything different. Good luck and let us know how you go!
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