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Danirudo · 03-27-2023, 08:42 PM

I have seen a few forum posts with the same issue as me with a few saying the sound is the torque converter and replacing it fixed the problem while others failed to find the cause of the noise.

I have a 2014 335i xdrive that is completely stock other than an intake

The sound is a knocking sound that only comes when the car has been driven and is also only really heard when in park or stopped (loudest in park or neutral). When in park or neutral, raising the revs makes the sound slightly louder and it increases with the revs of the engine. After around 1,500 rpm, the sound goes away. It isn't clear if that is because the engine drowns out the noise or the sound does actually go away. You can hear this in the second video linked below.

I first heard the sound roughly a month ago and when I went under the car it sounded like the noise was coming from the bell housing area. I then took it to two different shops, one being a German car shop and the other being a transmission shop. Both said that the noise was coming from the bell housing and not from the engine. The transmission shop said it sounds like it could be from the pump in the transmission while the other shop said that it is generally coming from the bell housing. The German specialist shop said that they did find videos of the same sound caused by a torque converter. Although both of these shops "think" they have an idea of what the problem could be, neither are sure and told me to monitor the issue. However, I want to fix the issue asap as a noise the car isn't supposed to be making cannot be good for it.

So I just wanted to know if anyone has experience with this and if so, what was the fix? It is not a horrible sound and as you can hear from the video it is not extremely loud, but definitely noticeable (its louder and more pronounced in person).

Side note: The technician said that the pump is directly beside the torque converter. In the video the sound may be hard to hear without headphones but it is a faint knocking/tapping sound.

video 1:

Video 2: https://www.youtube.com/shorts/IK_slV-We_o

03-27-2023, 08:42 PM	#1
Danirudo New Member 0 Rep 5 Posts Drives: 2014 335i Xdrive Join Date: Mar 2023 Location: Calgary Alberta Canada iTrader: (0)	Knocking sound from bell housing I have seen a few forum posts with the same issue as me with a few saying the sound is the torque converter and replacing it fixed the problem while others failed to find the cause of the noise. I have a 2014 335i xdrive that is completely stock other than an intake The sound is a knocking sound that only comes when the car has been driven and is also only really heard when in park or stopped (loudest in park or neutral). When in park or neutral, raising the revs makes the sound slightly louder and it increases with the revs of the engine. After around 1,500 rpm, the sound goes away. It isn't clear if that is because the engine drowns out the noise or the sound does actually go away. You can hear this in the second video linked below. I first heard the sound roughly a month ago and when I went under the car it sounded like the noise was coming from the bell housing area. I then took it to two different shops, one being a German car shop and the other being a transmission shop. Both said that the noise was coming from the bell housing and not from the engine. The transmission shop said it sounds like it could be from the pump in the transmission while the other shop said that it is generally coming from the bell housing. The German specialist shop said that they did find videos of the same sound caused by a torque converter. Although both of these shops "think" they have an idea of what the problem could be, neither are sure and told me to monitor the issue. However, I want to fix the issue asap as a noise the car isn't supposed to be making cannot be good for it. So I just wanted to know if anyone has experience with this and if so, what was the fix? It is not a horrible sound and as you can hear from the video it is not extremely loud, but definitely noticeable (its louder and more pronounced in person). Side note: The technician said that the pump is directly beside the torque converter. In the video the sound may be hard to hear without headphones but it is a faint knocking/tapping sound. video 1: Video 2: https://www.youtube.com/shorts/IK_slV-We_o Last edited by Danirudo; 03-27-2023 at 08:54 PM..
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