Automatic transmission fluid - durability in the transmission

I currently have an A3 gasoline-powered car, model year 2002, with 51,000 kilometers on the odometer.
My parents' car, which is over 90 years old , is like new. The inspection yesterday was no problem at all; nothing was noted, as usual. Since the last technical inspection, only 63 kilometers have been driven, haha..
Okay, here's the translation:

Now, my question:
The transmission shifts very poorly, and it gets worse the warmer it gets. Sometimes, unexpectedly and for no apparent reason, it downshifts in the city and then upshifts again. However, sometimes it shifts normally and well, especially when it's cold. Occasionally, above 80 km/h, it feels like the clutch is disengaging – you have to wait for the car to slow down, and then the transmission automatically downshifts. After that, you can accelerate again, and usually everything is fine for a certain period (minutes).
By the way, my parents never drive the car at 80 km/h, so I haven't really noticed much about that.

At Audi, they were probably sure that the torque converter was defective and that it's no longer worth repairing - the estimated cost was 1600€.

Personally, I suspect the problem lies with the transmission fluid, which is definitely 19 years old. The car has never been serviced at a garage. According to my father, only the engine oil and spark plugs were regularly changed at the gas station.
I mean, transmission fluid that's 19 years old can't possibly still have the viscosity it needs for proper torque transfer in the torque converter, right?

What do you think about it?

hkss wrote:

By the way, the car never goes 80 km/h when my parents are driving, so I haven't used it much for that purpose yet.

If I were you, I would first change the transmission fluid (or have it changed) and then observe the shifting behavior. Until then, I wouldn't worry about any potential defects.

Good evening.

It is likely that the aging process has had a much greater impact on the vehicle than the mechanical stress caused by the driver.

I'm not Audi's lawyer or spokesperson, but do you doubt the statement that the transmission is defective?

Okay, 51,000 km is quite low mileage for an automatic transmission, but you also have to consider the age of the oil and the long periods during which the oil wasn't circulating within the transmission. The humidity inside the gearbox further contributes to the aging process.

I can imagine that the solenoid valves in the slide valve housing might be stuck.

Have you checked the possible parameters using VCDS?


If you have the opportunity, change the filter and the oil. It definitely won't cause any harm. Don't expect miracles after the change, though. If you're lucky and things improve, you might consider whether to make another adjustment at a later time.

This is simply because the amount of oil being replaced is less than the total amount in the transmission. With another change, you would increase the amount of new oil in the transmission.

If the vehicle is otherwise in good condition, I'm sure a good used gearbox can be found.

If possible, delete the learning values.


Best regards,

Hi,

I find it hard to imagine mechanical damage given such low mileage.
More likely culprits include transmission oil that has deteriorated, rust, clumping, or seals and gaskets that are no longer sealing properly. Stuck valves or similar issues.

I would change the oil and drive the car for a few hundred kilometers. Just swap cars.
Fresh oil and movement can sometimes help to "regenerate" and cause slightly shrunken seals to swell up to a certain extent.

Best regards, Rainer.

I would definitely invest in a transmission fluid flush right away; that way, the torque converter will also get fresh oil.

Hello...


Based on your description of the problems, it seems like the issue might be related to the oil/oil level, the filter, and the gasket of the same component.
If no noises are audible and, otherwise, there is sufficient traction at the lower gear levels (low RPM), then the torque converter and clutch packs are not the issue.

Since I've performed several transmission flushes on various vehicles, I would advise you to address that issue first.
As the ATF fluid ages, it thickens, making it much harder to pump, especially since automatic transmissions always have a suction filter. This filter is inserted from below into the valve body with a sealing ring (the transmission oil pan must be removed) and is held in place by the oil pan. Almost all of the sealing rings I have replaced during filter changes were rock hard and no longer sealing properly. This results in less oil being drawn in, and air entering the system, which leads to a loss of power.

Okay:
Get a filter set, including an oil pan gasket and a sealing ring.
A good complete set might include, for example: Prices are around €20-25.

Get the CORRECT oil, DO NOT use any current VW-Audi oil.
While it's supposed to be backward compatible, it doesn't work at all in this old transmission because it's far too thin.
Please only use HP4 or HP5 oil, the manufacturer is not important, but preferably a branded oil.

The gearbox has a service fill capacity of approximately 3 liters and a complete fill capacity of approximately 5.3 liters.
approximately because these transmissions are filled based on their level at a specific temperature, rather than by volume.

The oil level should be checked and adjusted at a temperature of 30-35°C (read using VCDS in the transmission control unit) with the engine running.
Too little or too much oil can cause problems.
Fill with cold fluid, start the machine, continue filling until it overflows, then run with the lid open until it reaches 35°C. Oil will leak out during this process, then close the lid. It's done.

Regards, Mpire.

Mpire wrote:

Hello... Based on your description of the problems, it seems like the issue might be related to the oil/oil level, the filter, and the gasket of the same component. Greetings Mpire

Thank you very much, Mpire. You encouraged me to get the oil changed, and you predicted an excellent result, which proved to be true.
The transmission is now shifting almost perfectly again. It's like night and day!

Unfortunately, I can't do things like that anymore. I don't have a workshop anymore, and going to the car with a skateboard on the street is too dangerous for me at my age; it's just not possible.

Your suggestion about using the oil (HP5) is probably good, but of course, Audi wouldn't listen - they insisted on using the oil that is specified for this car.
Luckily, I was able to convince her to replace the rubber seal that seals the filter.

Okay, I'll think about having the transmission fluid changed again to make sure fresh oil also gets into the torque converter. It's sure to be cheaper than this time, but it's not exactly cheap.

P.S. I still need to ask why the brand new battery that I bought three days prior and had fully charged was charged again at Audi .

Hello.

I'm glad it's working again .

They (at least according to the invoice) filled it with ATF G052162A2. That's equivalent to ATF5 or HP5, everything's good, perfectly right.
Then, for once, everything runs normally in that workshop.
The three major service centers in our area (Nuremberg/Regensburg/Wackersdorf) only use the new green HP8 ink, with the corresponding consequences.
Before switching to a different oil, I would drive it for a good while, possibly change the 3 liters of oil again after 15,000 miles, and that should be good.
I think the new filter, the sealing ring, and the correct oil level probably made the biggest difference.

The switching will improve further once the controller has learned the new parameters.

Regards, Mpire.