Help - e53 Knocking from transmission - VIDEO
 

Hi guys

hoping someone can help with some internet diagnosis as it's a public holiday here and no mechanics open.....

This sound has crept up on me in the last 24 hours.....

It's present from about 20 seconds from start up, in all gears, and including when driving or rolling in neutral.

I have run BMW Scan 1.4.0 and no codes present

Using a garden hose and a screw driver as a listening device, it's not coming from the top end, not coming from the block - but I can hear it clearly through the transmission mounting point and it's coming directly out of the inspection hole under the transmission (which is where the first video is shot from)

Torque converter, flex plate, flywheel......I'm at a loss?

http://vid16.photobucket.com/albums/...ps11s0verf.mp4

This second vid shows the sound settling in soon after startup, it increases with a rev and then dies off after the revs return to idle but quickly comes back.

http://vid16.photobucket.com/albums/...pszxlgfvjz.mp4

Any help much apppreciated

is it possible the fly wheel is loose?

No idea, I can't see much through the inspection hole and although i did stick a screwdriver in there while the car was off to see if I could sense any play, no luck.

The car itself seems to be driving fine. Just sounds crook and not very 'BMW'.

IMO I wouldn`t drive the x5 until you know exactly what that noise is?

Sounds like a LOTUS, Lots Of Trouble Usually Serious.

If it was a petrol engine I would say it was piston slap.

It's puzzling that you don't hear it topside, because I agree that it is extremely similar to the sound of piston slap. I had that exact problem in a GM diesel when three wrist pin bushings wore out. My second thought would have been valve train since it was so constant with RPM. But if you can really only hear it from the bottom end, I have to lean towards a rod bearing.

2002 X5 3.0 265,360 miles
2004 325i 116,000 miles

Diesel History - 1981 Pontiac Bonneville 5.7L Diesel 264,000 miles

I would unhook the oil pressure sending unit and hook a gage up.

Thanks guys, I will take it to an Indy today and see what they say.

I forgot to mention, at the end of the video I had to crop off the section where I took off the oil cap and listened to the valve train - the sound isn't related, different frequency.

I hope this is a simple fix, but my gut says otherwise.


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I took it past a trusted mechanic this morning. He and another guy spent about 20 mins with it up on the hoist with a stethoscope trying to diagnose, but were pretty baffled. Hard to isolate the noise.

He feels it isn't a bottom end knock as they're normally present from the moment the engine starts, where as mine comes on about 20sec after starting (cold or hot). Obviously there are no certainties without opening the motor, but he did feel that it was a top end issue, perhaps a sticking lifter that was perhaps echoing down. His advise at this stage is to drop the oil, inspect for metal, then put in an lifter additive (not his preference, but at this stage he said anything is worth a go).

I'd already planned to do an oil and filter change this weekend, so I guess we'll wait and see.

Has anyone done a hardcore engine flush before? Something like Liqui Moly Engine Detox? I don't generally like putting in additives as they're often bandaid fixes, and an all out engine flush could dislodge some nasty stuff and move it into places it doesn't want to be........but any feedback is welcome.