Audi A3 8L: Transmission Noise Diagnosis

Hello everyone!

A long time ago (about 6-8 months), I reported in a thread about barely audible transmission noises.
After approximately 20,000 km of additional mileage, the grinding noises are unfortunately getting louder .
The noises occur regardless of the gear selected, including when the vehicle is idling. I also couldn't detect any difference between driving in curves and driving straight, which should normally be noticeable with wheel bearings.
The grinding noises are most noticeable at speeds between 50 and 80 km/h when idling, or in 4th or 5th gear while coasting.

I'm afraid that the differential or the axle drive shaft may be damaged. It's also possible that one of the gearbox bearings (input shaft, output shaft, differential) is worn out. However, I don't know how to make a more precise diagnosis of the problem without disassembling the gearbox. Do you have any helpful tips?

/Speculation mode on
Have you ever experienced or heard of a case where the noise from a faulty wheel bearing during cornering did not change, or changed only slightly, such that the noise was also noticeable during straight-line driving at almost the same intensity?
/speculation mode on

"Who among you has experience with gearbox repair? How time-consuming is it to replace the gearbox bearings yourself, or to replace the gear pairs in the axle ratio? What special tools are required for this?"

Thank you for your help.

Regards,
Alex.

Hello,

Quote:

Have you ever experienced or heard of a case where the noise of a defective wheel bearing during cornering did not change or changed only slightly, so that the noise was also noticeable during straight driving with almost the same intensity?

Yes, that was the case with one of the wheel bearings on my A3. The other one, which failed 20,000 km later, could be clearly identified.
As long as the noises aren't too loud: stay calm and continue observing. You might want to jack up the vehicle and manually rotate/wiggle the wheel.

If it's completely broken, at least you know where to start looking.

Best regards, Rainer.

Hi Alex,

donalexo wrote:

/Enable speculation mode. Have you ever experienced or heard of a case where the noise from a faulty wheel bearing during cornering did not change or changed only slightly, such that the noise was also noticeable during straight-line driving at almost the same intensity? /speculation mode on

a case?
Several!
"On my Golf, I've now experienced wheel bearing failures for the third time. They make a knocking sound while driving straight, at irregular intervals, almost like the shock absorbers are broken. I first encountered this issue on my older 1Z model. Shortly after, a colleague's Golf experienced the same problem, and just a few days ago, my parents' Golf was affected as well."
Normally, I'm used to hearing a grinding or howling noise from a faulty wheel bearing, especially when turning, but in this case, the noise is almost constant, both when turning and on straight roads.

Hi Alex!

I agree with the others; I've previously owned a C4 and a Clio that both experienced similar wheel bearing problems. Each time, it sounded like a problem with the main bearing of the transmission, but it never was.

Based on your description of your route, I also strongly suspect that these are the warehouses you're referring to.

Hi,

I can also confirm this, at least for the Golf 3.
First, there's a constant noise for a while, and if you wait long enough, like I did, you'll also hear the infamous 'lager' noise when cornering.
Therefore, I would say: Hold still and observe.

Regards,

Andy.

My dad's old Passat had the exact same problem. It made a grinding noise, both straight ahead and when turning! It turned out to be a wheel bearing.

Thank you for your postings!

Your statements make me a little more relieved, because a transmission failure after only 153,000 km would be quite bad. I hope you are right.

However, I'm not entirely sure about that, because I had a wheel bearing failure on the front left last summer, and that bearing shouldn't be the issue anymore (unless the workshop did a shoddy job ).
I was able to clearly identify this wheel bearing issue because the noise only occurred when turning right and was only really noticeable at speeds above 80 km/h. The bearing damage was practically inaudible when driving straight.

As I've already said, I hope you're right and it's "just" a wheel bearing. I really don't feel like having the transmission repaired or replaced .

Has anyone else in this forum experienced a gearbox or gearbox bearing failure? How did it manifest itself?

I can actually detect a slight load-dependent variation in the noise, meaning there's a difference in the sound depending on whether I'm in pushing or pulling mode. Unfortunately, this doesn't bode well.

Let's see how things develop.

Regards,
Alex.

donalexo wrote:

Has anyone else in this forum experienced a transmission damage or a transmission bearing damage? How did it manifest itself?

... Yes, but not with the TDI.
My JB had differential damage. In very specific curves (and therefore with differences in wheel speed), I heard a rattling sound. Whether I steered more (or less), it was quiet again. I always wanted to investigate the cause of this, and the transmission has been in storage for 15 years now...

Here's a brief update:

Given the relatively high temperatures tonight, the noise was even more noticeable than usual. It's now occurring even at very low speeds, around 40 km/h. The noise is almost constant, regardless of whether the clutch is engaged or disengaged.
Anyway, it's making a pretty significant amount of noise, enough to make a mechanical engineer feel quite anxious and uneasy.
Meine Frau würde das Geräusch sicherlich noch gar nicht wahrnehmen. TYes, that's life.

Regards,
Alex.

Hello Donalexo,

My father had an Audi 100, type 43, manufactured in 1990, with a four-cylinder engine (90 hp). From approximately 200,000 km, it also made a terrible, speed-independent humming noise. At 250,000 km, we replaced the transmission (with a used one). After that, the noise was gone for more than 60,000 km, but then it returned. Around 330,000 km, the car was sold and went east, with the noise still present.

With Audi 80 and 100 models from these years, this noise is often heard more frequently, even from outside the car as it passes by.

'The five-cylinder Audis from those years sometimes make a similar noise, but it disappears when the clutch is disengaged. Apparently, it's supposedly related to some kind of bushing in the area of the release bearing.'

Regards,
Thomas.

Hi,
Type 44, by the way. My car also makes similar noises. When I first noticed it, I suspected the winter tires, but unfortunately, the noise persisted... Changing the transmission oil didn't help. There were also hardly any metal shavings in the oil.

Hello everyone!

I went to the doctor yesterday because of the noise.
After a short test drive, the mechanic also tapped on the wheel bearing, explaining that he had rarely encountered transmission problems in TDIs.

Well, that somehow makes me feel more relaxed .

To diagnose the problem, he explained that they would need to drive each wheel individually to determine which wheel bearing is faulty.
Okay, that's fine, but I believe that this will take a lot of time and therefore cost money, and that it's unnecessary because the left front wheel bearing was replaced last summer.

According to that, I'll just replace the right front wheel bearing and that should be it. Or what do you think?
If it turns out to be the left one again, I can have it replaced for free because it's still within the warranty period.

Regards,
Alex.

Hello everyone!
According to that, I'll just replace the right front wheel bearing and that should be it. Or what do you think?


Both sets of tires are about the same age, so I'm going to swap all four right away. The effort involved isn't much, and they're not that expensive.

Hello everyone,

in den letzen Tagen ist mir aufgefallen, dass mein Golf III Bj. 93, 1.9 Diesel, 64PS mit knapp 420tkm auf der Uhr (bis auf Lichtmaschine noch alles original) in den ersten 20 km pfeifende (pfeifen: trifft es wohl am ehesten) Geräusche von sich gibt, die ab ca. 50 km/h einsetzen bis man sie durch die Windgeräusche nicht mehr wahrnimmt. Beim Langsamerwerden wird der Pfeifton ab 50 km/h wieder tiefer und setzt so ab 40 km/h aus. Vom Motor her kann es nicht kommen, da ich den während der Fahrt bereits mal ausgemacht habe. Beim Bremsen, Lenken, Beschleunigen und Auskuppeln pfeift er weiter konstant. Erst unter 40 km/h gibt er wieder Ruhe. Nach den ersten 20 km fahre ich 30 km auf die Autobahn bei ca. 130 km/h. Fahre ich dann runter ist das Geräusch weg, erst beim nächsten 'Kaltstart' beglückt es mich wieder. Da sich die bewegenden Teile beim Rollen bis ins Getriebe erstrecken, könnten die Geräusche auch von da kommen. Soweit ich weiß, hat sich noch niemand um das Getriebe gekümmert, da es ja 'wartungsfrei' ist. Kann It could be due to the transmission oil or something similar.

Thank you very much for your efforts!!!

Christian