A3 Getriebe kaputt? 3.4.5. Gang gehen nicht. | Posts 16+

13-09-2010, 2:24 Subject:

Hi,
I'm currently looking at the design of the CZL gearbox.
http://vagcat.com/epc/cat/au/A3/1997/201/51/2399058/,
http://vagcat.com/epc/cat/au/A3/1997/201/51/2399243/,
http://vagcat.com/epc/cat/au/A3/1997/201/51/2399827/,
What position does the side lobe occupy between the second and third?
Sure, here is the translation of the text from German to English:

"vg"

This is a common abbreviation for "very good" in German. It is often used in online forums and chat rooms.
Herbert.

13-09-2010, 10:15 Subject:

The images, or whatever they are supposed to be, cannot be opened.
The sideband is the sideband.
The distance between the 2nd and 3rd gear stages on the countershaft is located between the 2nd and 3rd gear pairs.

13-09-2010, 20:09 Subject:

Hi,
I think we should postpone this discussion until you post the photos of the damage. Maybe we're just talking past each other.
If you are interested, the source of the images I linked is http://www.vagcat.com/.
Sure, here is the translation of the text from German to English:

"vg"

This is a common abbreviation for "very good" in German. It is often used in online forums and chat rooms.
Herbert.

24-05-2011, 14:55 Subject:

Okay, here's the solution.
Mir hat es doch tatsächlich diese Welle zwischen 2. und 3. Gang torn apart.
The last picture shows it best.
The designed weak point likely prevented more serious damage.
It's funny that it broke during the gear change, not while engaging the clutch.
I have to admit that I didn't take good care of the transmission, and it was certainly subjected to higher loads due to the chip and the sports clutch.

If someone needs spare parts for the CZL gearbox, just let us know

.

Tagessuppe · 24-05-2011, 20:41 Subject:

Hi,

I took a look at the fatigue crack script, and your damage appears to be caused by crack growth at a low nominal stress and a mild notch, likely due to circumferential bending.
The rough surface was the remaining cross-section that was torn off last; the crack started on the edge, opposite to it.

VG
Findus170

24-05-2011, 22:45 Subject:

Okay!
This shell-like growth at the fracture point also led me to this conclusion.
So, it seems this phenomenon is well-known?
Would you still say that the chip tuning and the sports clutch, along with my driving style, were to blame?
Or would that have happened regardless?

24-05-2011, 22:49 Subject:

Tagessuppe wrote:

Would you still believe that the chip and the sports clutch, along with my driving style, were to blame,

Not guilty, but certainly contributing factors.

25-05-2011, 8:25 Subject:

How many kilometers were on the transmission?

Best regards, Rainer.

25-05-2011, 8:39 Subject:

So, this is the drive shaft? It's remarkable that, despite the one-sided bearing and the breakage, some of the gears were still usable.
hg
Herbert.

25-05-2011, 9:19 Subject:

Tagessuppe wrote:

Correct!
This shell-like growth at the fracture point also led me to this conclusion.
So, it seems this phenomenon is well-known?
Would you still say that the chip tuning and the sports clutch, along with my driving style, were to blame?
or would that have happened anyway?

Well, I would say that a surfboard made of flawless material probably wouldn't have broken.
However, I am not aware of any other cases of damage to this gearbox.
This is a fracture failure caused by stress, and there must be a starting point for crack growth. In my experience, the notch alone is usually not enough; there needs to be another factor involved. You should carefully examine the shaft, especially the edge opposite the remaining fractured section, to see if there's any irregularity in the grain structure or any signs of a pre-existing crack.

best regards
Findus170

25-05-2011, 9:56 Subject:

Hello Rainer!

The transmission had 320,000 km on it, of which I drove 230,000 km with a performance chip and 150,000 km with a Sachs performance clutch.
My driving style is usually very relaxed and focuses on using torque, which the long 5th gear (0.68 instead of 0.717) further enhanced.
The old Luk clutch started slipping relatively quickly and likely only transmitted around 300-350 Nm of torque (depending on the temperature).
The clutch has such a strong grip that it hasn't even shown the slightest sign of slipping, even when engaging quickly in higher gears.
I would estimate it to be around 500-600 Nm.
Or could the much stiffer torsion suspension of the driving disc have played a role?
It doesn't matter. I think that's not so bad

at 320,000 km.
The used gearbox with 80,000 km on it cost me 170,-, which is exactly what the long 5th gear would have cost.
Nowadays, I only needed 6 hours to replace the gearbox.

25-05-2011, 12:29 Subject:

Okay, so it doesn't sound so bad and rather normal.