Automatic Transmission Repair: VW Passat 1.9 TDI

Hello,
Can anyone help me?
I drive a 1998 Passat TDI (AHU) with a 4-speed automatic transmission.
The vehicle has the following issue:
The transmission shifts very roughly between the 2nd and 3rd gears; specifically, the shift to 3rd gear is jerky when there's no load, but it shifts smoothly under load.
I have already replaced the sliding case, but it didn't improve anything. Volkswagen wanted to install a new transmission, but that was too expensive for me.
The car has approximately 185,000 kilometers on the odometer.
I hope you have some ideas.

Regards,
Dietmar.

Hi Dietmar,

'With a 98 [model], shouldn't it already have a 5-speed transmission?'

'Never mind... so, replacing the hydraulic control unit didn't solve the problem?'

Then I'm betting on a broken coil spring.

Greetings from Lake Constance.

Tobias.

Hello everyone, hello Dietmar.

You asked me what the function of a Belleville washer is in a gearbox.

Since I think this might interest more people, I'm quickly posting it here.

During the rapid filling of the clutch, the clutch piston moves towards the friction disc pack. To ensure that the 'engagement' of the piston with the friction disc pack is smooth (without any noticeable jolts), coil springs are used.
These are hardened steel discs in the shape of a corrugated washer, only much larger.

'Well capacitors are also needed in rolling circuits to prevent switching spikes.'

Greetings from Lake Constance.

Tobias.

Hello Tobias,
Thank you for your reply.
How do you replace the leaf spring?
Could it really be due to that part?
The circuit works with...
It's better (good) in other gears.

Regards,
Dietmar.

Hi,

It's possible that the other circuits are working correctly...in fact, it's quite likely.

Since each clutch or brake in the stepped automatic transmission has its own coil spring.

But:

Such 'remote diagnoses' are always just guesses or based on experience.

I can't tell you how it's changed in your transmission.

But definitely remove the gearbox, disassemble it, inspect it, reassemble it, and install it.

Greetings from Lake Constance.

Tobi.

Hello Tobias,
It sounds like a lot of work (disassembling the transmission, etc.).
I suppose I'll just have to live with the problem. My wife drives the car anyway, so I only have to put up with her complaining about it occasionally. It will pass.

Too bad, I thought more people would respond to my message.

'Nevertheless, thank you very much for your effort.'

Regards,
Dietmar.