# Mysterious N55 knocking



## Ssilver356 (Apr 4, 2021)

Hello everybody 
I post in this section because this engine is used in several BMW models.

I have a knocking noise on my 640i F06 2013 when engine is warm and at idle only in Park or Neutral. Car and shifting runs fine.

If I move to Drive or Reverse the noise goes away.

I have seen many videos on youtube and i don't found the issue in comments.
Sometimes engine replacement, torque converter, rod knock, exhaust bolt, normal..

I have already removed the belt to eliminate noise of front accessories. Noise seems coming from rear of engine or between transmission and engine.

Some links :


























F30 335i klackern

I would like to know your opinions before removal of my transmission which is little pain.
Thanks for help


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## Ssilver356 (Apr 4, 2021)

No ideas ?


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## Ssilver356 (Apr 4, 2021)

Bump


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## Ssilver356 (Apr 4, 2021)

Here is a video of mine :






When i pull some gas and release, we can ear the noise quicker than the speed of motor

And when I select second gear the noise goes away


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## dziuraski (May 14, 2021)

Ssilver356 said:


> Here is a video of mine :
> 
> 
> 
> ...


Did u find solution of this knocking ?


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## Ssilver356 (Apr 4, 2021)

dziuraski said:


> Did u find solution of this knocking ?


Not yet do you have same symptoms ?


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## dziuraski (May 14, 2021)

Ssilver356 said:


> Not yet do you have same symptoms ?


n20 2013 x3. Yes. after using the stethoscope, a thumping noise comes from where the gearbox oil pump is located, which is the front of the gearbox at the level of the oil pan. my gearbox is on table my mechanic is looking for a problem. to check the oil pump drive, the pump itself, converter, no idea what to do next. will inform you about the progress


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## Ssilver356 (Apr 4, 2021)

dziuraski said:


> n20 2013 x3. Yes. after using the stethoscope, a thumping noise comes from where the gearbox oil pump is located, which is the front of the gearbox at the level of the oil pan. my gearbox is on table my mechanic is looking for a problem. to check the oil pump drive, the pump itself, converter, no idea what to do next. will inform you about the progress


Yes the sound is located in torque converter area. I have removed my gearbox too, in 2 youtube videos the solution was replacing torque converter. So I have send my torque converter for repair in Poland, I waiting for it to re-install gearbox and hope the fix this issue..

Yeah tell me if your mechanic find a problem with oil pump.


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## dziuraski (May 14, 2021)

Gearbox repaired, the knocking sound is gone.What have i done?. Torque converter was regenerated, it was not damaged but badly worn. No sign of damage to the gearbox inside. Oil was old for 120k km. We also pulled out the oil pump assembly, it was in very good condition, no need to be replaced. New oil pan, new oil, adaptation reset and its working with some gear change issue but it is probably due bad adaptation process.


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## Ssilver356 (Apr 4, 2021)

dziuraski said:


> Gearbox repaired, the knocking sound is gone.What have i done?. Torque converter was regenerated, it was not damaged but badly worn. No sign of damage to the gearbox inside. Oil was old for 120k km. We also pulled out the oil pump assembly, it was in very good condition, no need to be replaced. New oil pan, new oil, adaptation reset and its working with some gear change issue but it is probably due bad adaptation process.


Thanks for sharing your experience 👍
I am still waiting for my regenerated torque converter ( from moto-jaca inowrocław Poland ) and my car is around 120 000km too. 

Where is your mecanic ? Do you know if theses seals were replaced ?


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## dziuraski (May 14, 2021)

I send my torque converter here "MVS Regeneracja Konwerterów" https://www.mvs.auto.pl/
I replaced every seal down to oil pump include aluminum bolts to the oil cover plate.
I bought bolts from BMW oem number 24277604965 there are both seals inside.
If not, here is gasket kit seals https://maktrans.net/zaptchasti-akpp/bmw1/zf8hp45_8hp55_8hp70/gasket-kits-ZF-8HP45/Komplekt-prokladok-ZF-8HP45-00-up-21501A
Good luck.


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## Ssilver356 (Apr 4, 2021)

dziuraski said:


> I send my torque converter here "MVS Regeneracja Konwerterów" https://www.mvs.auto.pl/
> I replaced every seal down to oil pump include aluminum bolts to the oil cover plate.
> I bought bolts from BMW oem number 24277604965 there are both seals inside.
> If not, here is gasket kit seals https://maktrans.net/zaptchasti-akpp/bmw1/zf8hp45_8hp55_8hp70/gasket-kits-ZF-8HP45/Komplekt-prokladok-ZF-8HP45-00-up-21501A
> Good luck.


Yes I have bought this KIT of seals, but in my case I have not open the gearbox so i don't need to replace aluminium bolts.

Another question about refilling oil of the gearbox : have you follow the ZF procedure ? First fill + 0,5L ?



Thanks


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## dziuraski (May 14, 2021)

Hi I do exacly like in this yt film


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## Ssilver356 (Apr 4, 2021)

dziuraski said:


> Hi I do exacly like in this yt film


Ok have you pre-filled the torque coconverter before installing ?


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## dziuraski (May 14, 2021)

Yes about 0,5-0,7 litre


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## Ssilver356 (Apr 4, 2021)

Bad news..

I have re installed the gearbox with regenerated torque converter and :


the knocking sound is still present when warm
Now the car is jerking when decelerating between 2000 rpm and 1500 rpm ( like braking )
Sometimes slipping when accelerating
Sometimes vibration like a bumpy road and droning sound

However no problem with shifting and when I accelerate over 3000 rpm no problem.

New torque converter ? Engine mounts ? Problem with driveshaft ?

I am lost..


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## Ssilver356 (Apr 4, 2021)

@dziuraski can you check your private message please.


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## Ssilver356 (Apr 4, 2021)

Another vid of the knocking noise, after (bad) regeneration of the torque converter, there is an additional rattling noise :






Here is a vid with the torque converter disengaged :






So the noise is 100% coming from transmission, gearbox or torque converter.


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## Ssilver356 (Apr 4, 2021)

Update : the torque was not regenerated correctly.

I bought a new one from ZF partner ( ~800$ ) because BMW sell it 2400$ 

No more knocking car runs fine


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