Any Transmission Noise Updates? - The Unofficial BMW M5 Messageboard (m5board.com)

hotbimmer · 16th July 2001, 20:14

Ok....I have 1000 miles on my M3 and the clanking noise from 1st to 2nd gear is still noticable. I was wondering if anyone here has any new information on why that noise is there. I am due for my 1200 mile service soon and would like to arm myself with some information before I go into the dealer.

Any information would be greatyl appreciated.

MAVERICK · 21st July 2001, 11:02

A service bulletin has been issued that this noise is caused by the new limited-slip differential when shifting from first to second at low engine speeds. The cause of the noise is from a very slightly mis-aligned flange from the right, rear, half-shaft. BMW engineers have said that this is normal and there is no fix for it.

Hopefully, the problem will be solved for the MY2002 cars which will start production in Sept.

hotbimmer · 21st July 2001, 19:45

MAVERICK, thanks for the info buddy.

Mr. Grinch · 22nd July 2001, 00:52

Apparently there is some extra play on one of the output shafts of the new differential, responsible for the noise. BMW says this is normal.

BMW stated in the bulletin not to replace anything unless damage can be verified. From other M3 owners, some damage has been verified. In some cases, bolts were found to have sheared at the output of transmission and/or differential. In another, the differential fluid was drained and found to have metal filings in it, more than considered normal.

So there are a few things your dealer can / should check before deciding if your car is "normal" or not.

hotbimmer · 22nd July 2001, 01:52

Great Mr. Grinch:

Thanks for the info. I just printed this thread out.

Now I will tell them what to look for on August 6th. I've already set an appointment.

sscaro · 23rd July 2001, 00:04

If I understand this correctly, it sounds to me like whether there is actual damage might depend on how the car is driven and not on the defect itself. Somene who is easy on the car would likely not shear bolts while a more aggressive driver might.

Regardless, if I had just bought an expensive new M3 with this defect I would do my best to have them repair it now or agree to repair under warranty regardless of mileage if there were ever a problem related to this defect.

One would expect a company the caliber of BMW to make good on something that is not right.

Mr. Grinch · 23rd July 2001, 00:59

It's definately not a great situation. I hate to point fingers at BMW purely on 2nd and 3rd hand information. But from the posting of the bulletin, which you can find if you ask on www.bimmer.org, they did not seem to resolve the issues, at least not in my mind.

Certainly some people have had bolts shear and rear diffs die. And on the other hand, certainly BMW should not encourage replacement of transmissions and diffs where there is no problem.

But the biggest complaint, the clunking noise itself, they have failed to explain adequately. Certainly there are E36 M3 drivers who had this issue, and now have it in the E46. It's never caused them problems in their E36 and so it doesn't bother them to have it now.

But on the other hand, we have E36 and E46 M3s with _no_ clunking noises. So you've got a case where people know BMW's capable of selling a quite trans / diff, but just not for them. The people who've had a quiet transmission in the past, regardless of if it was an M3 or not, don't find this a satisfactory answer.

I don't remember ever seeing any E39 M5 guys complain about this... and it's supposed to be the same transmission. I guess this does point to the theory of the output shaft off the differential, which is different from the M5.