Audi 80 Avant TDI: Vibration after rear axle swap

Hello everyone,

I replaced all the engine mounts in my Audi 80 TDI Avant last week.
swapped. I've replaced all the screws except for the bushings in the control arms.
Tightened while in the raised position (front wheels unloaded).
My problem now is that my TDI is vibrating excessively when I'm in the 4th or...
"Starting from 1200 RPM in 5th gear, it accelerates. I didn't have this vibration before."
If you let the car idle at 1200 RPM and then press the accelerator,
Does any part, even a new one, fit?
While installing the generator carrier, I noticed that the nuts...
The rear screws are located in elongated holes (perpendicular to the direction of travel).
How can I determine whether the AGT needs to be adjusted more to the left or to the right?
At "Freundlicher," they were amazed to discover that such long-bodied [cars/vehicles] exist - AMAZING.
Regarding the vibrations, I was advised there to check the screws that secure the AGT.
to release, while the car is on its wheels, the AGT.
and to move them back and forth, and then to tighten all the screws again.

I followed this advice, but it's still vibrating and hasn't changed.

The rubber-metal mount for securing the transmission on the passenger side.
I also replaced it (the old one was cracked and brittle).

I detached the bearing from the gearbox support - no change.

To test whether the vibrations are coming from the exhaust system, I have...
"These were unscrewed from the back of the KAT, but unfortunately, that didn't help either."

So, if anyone could give me a tip, I would be happy.
The feeling of despair and frustration is slowly starting to creep in for me.

Greetings.

MichaelJ

Hi,
Did you also replace the engine mounts? If not, it's possible that, now that the engine support is properly mounted again, vibrations from the engine are being transmitted through the engine rubber mounts to the body.
Are all the screws of the engine mount bushings tightened?
Another possible culprit is the torque support on the front crossmember. It may not be tightened in the correct position.
Regarding the long holes used for mounting the generator carrier, you should have the front axle geometry checked. Otherwise, changes in alignment (camber/toe) could cause the tires to wear unevenly.
However, vibrations are unlikely to be expected from that source.

Regards,
Olli.

Hello Olli,

First of all, thank you for the tips. I've already scheduled an appointment for the wheel alignment.
ist am Freitag. deswegen macht mich das mit diesen Vibrationen auch jeck. I see.
It's likely that I'll have to remove the aggregate carrier again, and then I'll be allowed to.
I will have myself measured again .
Regarding the engine mounts - on my Avant (B4), the engine mounts are directly attached to the body.
and have no contact with the supporting structure.
Only at the rear of the transmission, on the right side, is there a rubber-metal bearing that is attached to the engine mount.
It is (new), and on the left side, a support extends from the left transmission bearing to the rear attachment point of the AGT.
Otherwise, I haven't had access to any engine mounts. If the engine mounts are attached to the engine support, then...
If I were to understand, then worn-out aggregate carrier bearings would be the cause.
Vibrations are absorbed and the new (stronger) ones are passed on.
Or, due to the removal and installation, the position of the engine mounts may be incorrect.
But like this?
Or am I underestimating the rear gearbox mounts?

I also consulted with a former VAG-certified master mechanic. He also suspected the engine mounts.
and after reviewing the application, she decided to reject it.
Right now, I really regret doing everything all at once.
I had. If I had taken a test drive after each change, I would know where the problem lies.
lies buried.

Greetings.

MichaelJ

Hello!
I think that if the tire clearance is the same on both the right and left sides, and the wheel sits nicely centered in the wheel well, then the long hole adjustment should be correct.

I once had to remove the generator support from my own machine. Unfortunately, when I was reattaching it, one of the threaded plates in the frame, to which the generator support is attached, had disappeared!!
I then found a suitable nut, welded a washer to one side (so that it wouldn't rotate), and used a wire through a hole in the spar to guide the nut into the correct position!
I really don't want to do that anymore...
Okay, PAY ATTENTION!!!

Best regards, Wolfi.

@Wolfi

Hast Du danach Probleme mit Lastvibrationen im 4. und 5. How's it going?
Simply insert it - and it's done (excluding the hassle with the threaded insert).
Do you happen to know if, for the rear bearings, the metal plate should be facing upwards?
Does the design of the bodywork extend downwards as it does at the front, or do the elements point downwards at the rear?
A friend who owns an auto repair shop was supposed to sandblast and paint the AGT (presumably a part or component).
and he kindly changed the tires for me. Now I'm not sure if he...
he didn't make any mistakes.

I'm about to retrieve the generator carrier and contact Audi again.
to have it re-mounted - even though I don't understand how it could be causing vibrations.
or how it should be redirected.

Best regards, Michael.

No, I didn't experience any vibrations. However, I haven't replaced the bearings yet, which I plan to do soon.
Did you install Quattro batteries in your AGT? They should be more durable...

I'm not sure if the shelves are facing upwards; I would need to check.

I can imagine that a misaligned bearing could transmit vibrations from the transmission.

Hello MichaelJ!
I just checked: All 4 bearings are facing upwards! It seems the rear ones were installed incorrectly at your place.

@Wolfi

It's hard to believe but it's true: the bearings I just received, according to the documents, are supposed to fit my B4 Avant TDI with a manual transmission. I've now found the part number for the old bearings, and they are the ones for the TDI with an automatic transmission .
These are also found in another TDI. It also has a manual transmission. It looks like someone might have randomly entered the part number into the AKTE system .
Tonight, new shipments with the old product numbers are arriving - let's see what my vibrator does then - hopefully nothing.

Greetings.
MichaelJ

Okay, the correct generator carrier bearings are installed .
But it has only gotten slightly better .

Now, only two sources of vibration/rumbling remain for me.

1. The exhaust is somehow stressed or strained between the manifold and the catalytic converter - is this a common issue?

2.
The polyurethane bushings in the crossbeams are too stiff and are transmitting something.
Vibrations in the body - are there such vibrations in the area of the transmission, drive shafts, wheels?
Is anyone else using PU bushings in the crossbeams and not having any problems ?

I really don't feel like pressing the crossmember bearings back in, only to find out that...
that it wasn't actually due to that .

Welche Buchsen hast du jetzt verbaut? Part number?

"On the meckisforum, there are several TDIs with PU bushings, and I haven't read about any problems. I also ordered them - according to Gerd, there are no issues with TDIs."

In the engine mount, the parts with the numbers 8A0 199 415 B are installed at the front, and the parts with the number 8A0 199 419 are installed at the rear. Initially, I received the part with the number 8A0 199 419 A for the rear from my "friendly" supplier. This resulted in the installation process being different from what was described in the Audi repair manual, and the vibrations were more pronounced.
The PU bushings from Gerd are installed in the crossbeams. In another forum, I found someone else who is experiencing similar vibrations and is just as clueless about what's causing them.
He has Gerd's polyurethane bushings and the engine mount is rigidly mounted with aluminum bushings.
After reverting the rear engine mount supports to their original design, the vibrations in his Audi 80 TDI were reduced, but still noticeably strong.

"In my car, the vibrations/rumbling noises below 2000 RPM aren't so strong that they're painful, but they're inexplicable compared to an A4 TDI from 1996 with a 1Z engine and 200,000 km. With that A4, I can accelerate from 1200 RPM in 4th or 5th gear without any rumbling – it revs up 'smoothly'. My B4 (with 364,000 km) rumbles from 1200 to 2000 RPM, then increases between 2000 and 2400 RPM to the point where it rumbles and vibrates so strongly that loose objects start to rattle."

Tomorrow, I will detach the exhaust pipe behind the catalytic converter and unbolt it from the bracket that is attached to the transmission. Then, the exhaust pipe and catalytic converter will only be connected to the turbocharger.

If it's still vibrating, then, in my opinion, only the transverse support polyurethane bushings are likely to be the source of the noise. It might also be a matter of the car's mileage. After a certain mileage, the wear and tear on the transmission and drivetrain is so significant that the parts have "play" and this is transmitted through the rigid polyurethane bushings.

Regards,
MichaelJ

I've also been using Gerd's PU bushings for 1.5 years. However, I only experience a slightly increased amount of rattling noise.
The hydraulic mounts and gearbox rubber bushings are new; actually, almost everything has been replaced already, except for the rubber bushings on the engine mounting bracket.
The suspension struts need to be replaced sometime in the next few months.

Okay, I've compared the part numbers, and I'm completely lost now.

According to the Mecki's forum for Quattro owners:
857 199 415 B front.
857 199 419 B, rear.

(857/8A0 likely only refers to T89/B4)

According to sachs.de, for the 1Z:
8A0 199 415 B
8A0 199 419

The bushings for the quattro system are supposed to be stiffer, but apparently the front ones are the same.
"sachs.de does not list any rear tires for the quattro."

But what are the 8A0 199 419 A? From the automatic 1Z??

According to the Audi parts catalog, the part number 8A0 199 419 A is compatible with ***, 1Z, and AAZ engines.
According to my understanding of manual transmission TDi engines.
8A0 199 419 for ACE, ABK, ABM, ADW, ADA, AAZ and automatic transmissions: ***, 1Z.
Okay, so we're talking about TDI models with automatic transmissions. I had these bearings in my car as well.
Manual transmission included, and also found in another B4 TDI.
It's possible that the assignment was reversed, and the part number 8A0 199 419 A is actually the correct one.
B4 TDi models with automatic transmissions are the best.

Regards,

MichaelJ

Hello MichaelJ.

Have you solved your problem, or are you just living with it?

Hello Wolfi_b,

No, it's still vibrating. That's why I'm using the standard control arm bushings.
They don't transmit the vibrations as strongly.
The cause of the vibrations is located in the area of the engine, which runs very roughly within a certain speed range. The PU bushings then transmit these vibrations without any dampening.
continue.
When it gets warmer, I will replace the engine mounts.
The driver's side still looks good, but let's see what the passenger side looks like.
I cannot assess that.

Greetings.

Michael.