The D2 Forums

My observations are as follows:

In lower gears, at around 1500-2000 rpm, often with the engine under load (going up an incline), I get a shudder until the revs increase to above 2K.

It only happens when the engine/box is warm and it’s not got any worse in over 4 years.

But I do have an intermittent F125 fault on the VCDS -0 could it be that?

And where can I find a new F125 switch? Perhaps one of these https://www.autodoc.co.uk/car-parts/oem ... gIpg_D_BwE

The torque converter lockup clutch is toast. Either the friction material is worn out, or the seal on the piston is perished. The converter locks up (or tries to) at 1800 rpm, so as it passes through that speed you get the shudder as the lockup clutch is slipping slightly, just like judder in an ordinary manual clutch when it is worn out or contaminated.

A reconditioned converter is ~£500 or so. The challenge of course is replacing it, since it's sandwiched between the engine and gearbox.

F125 only tells the gearbox ECU what position the shifter is in and can be tested in vcds.

If your car wouldn't shift into any gear or the engine wouldn't start because the ECU wouldn't be able to see that shifter is in P, then f125 could be the cause.

If you are going to have the gearbox out for torque converter replacement, it would be a good idea to replace it at the same time.