520D auto / ZF 6HP possible problem..

[John_D]

Update. I did a lot of city driving today and car was at its worst. In D at idle pulsating vibrations causing the whole car to slightly shuffle side to side, like as if the engine was hunting but the idle was steady. Vibration could be felt gently accelerating from a standstill until around 30kph or so.

After an hour or so cooling down outside I went back out to the shops with inpa connected. Checked all values and everything looked ok. Gear oil temp approx 70-75C. When stopped at the lights the pulsating vibration was gone it just felt again like a rough idle... however this completely went away if I moved the gear selector across to sport and manually selected 1st.
So it seems it’s happening when stopped in 2nd gear only. And it seem that it’s highly dependent or gear oil temperature or viscosity since it gets worse as it gets hotter.(car is perfect when cold)

Am I right in saying it sounds like a knackered torque converter or lockup clutch?

I will check fluid level in the coming days, may also try a friction modifier additive.

[318 iS Cosmos]

Update. I did a lot of city driving today and car was at its worst. In D at idle pulsating vibrations causing the whole car to slightly shuffle side to side, like as if the engine was hunting but the idle was steady. Vibration could be felt gently accelerating from a standstill until around 30kph or so.

After an hour or so cooling down outside I went back out to the shops with inpa connected. Checked all values and everything looked ok. Gear oil temp approx 70-75C. When stopped at the lights the pulsating vibration was gone it just felt again like a rough idle... however this completely went away if I moved the gear selector across to sport and manually selected 1st.
So it seems it’s happening when stopped in 2nd gear only. And it seem that it’s highly dependent or gear oil temperature or viscosity since it gets worse as it gets hotter.(car is perfect when cold)

Am I right in saying it sounds like a knackered torque converter or lockup clutch?

I will check fluid level in the coming days, may also try a friction modifier additive.

Have you driven another one John? Happy to compare mine if you want?

[John_D]

Have you driven another one John? Happy to compare mine if you want?

I have not, but may take you up on the offer sometime if my head gets sufficiently melted

I remember how it was for the first year or so of ownership though, this is a new problem that has only manifested itself in the past few months so i have a good baseline for comparison.

situation update.. problem worsens with AC switched on, completely goes away if i select DS ,returns when i select D.

waiting for non-manky morning to do a proper inspection and fit the new TVD.

Cheers,
John