Troubleshooting an 8-speed automatic transmission

Hello everyone,

I'm having a problem with a Touareg 4.2 TDI that has an 8-speed Aisin automatic transmission.
The vehicle jerks briefly after shifting gears.
Only when upshifting, and between 1300 and 1800 RPM.
What seems strange to me is that the engine speed at idle does not correspond to the input speed of the transmission.
At a motor speed of 630 RPM, the gearbox input speed is 580 RPM.
Can someone evaluate this?
What measurement values and tests can I perform with VCDS to narrow down the problem?
The transmission flush has already been done.
There are no error codes stored in the control unit.

Best regards,
Raimund

This is the same topic as discussed here: /viewtopic.php?t=31873.
Here's some additional information. It's quite possible that the switching processes are not working correctly. Perhaps you should stick to one topic?
hg

Hello Herbert,

Thank you for your feedback.
Debugging is proving to be extremely difficult.
I thought a new topic focusing on the transmission would be better.
Can you answer the question about the different input speeds at the automatic transmission?

Best regards,
Raimund

Hi,
Between the crankshaft and the transmission input shaft is the torque converter. That's why you see different idle speeds.
I don't have any experience with automatic transmissions, but I'd like to ask: Does the jolt when shifting occur in all gears, or only in certain gears? Do you observe any short-term fluctuations in the speed?
Somewhere between the accelerator pedal and the wheels, the power flow changes, possibly in the transmission. Figuring that out without any prior knowledge is detective work.
hg
Herbert.

Hello Herbert,

The jolt only occurs when shifting gears.
It's most noticeable when the engine and transmission are cold.
When the vehicle is warm, the problem only occurs intermittently.
It only occurs within the partial load range, specifically between 1300 and 1800 RPM.
I think that in neutral, the input speed of the transmission should be equal to the engine speed.
But I'm not entirely sure about that.

Best regards, Raimund.

Hi Raimund,
Perhaps the jolting can be recorded during a measurement run.
The measured parameters are engine speed, gearbox input speed, and gearbox output speed. The fewer measurement parameters, the better the resolution.
Can you provide an overview of the measurement parameters for the Gasoline Direct Injection (GDI) system that are available in VCDS?
hg
Herbert.

Hello Herbert,

I'm going to do some test runs and adjustments.

Best regards,
Raimund