The Aisin automatic of the transverse engine VAG models locks the torque converter across a wide slip range, which gains on fuel consumption but loses on the life of the friction lining. The sign of wear is a vibration or "buzzing" felt at lock-up, and the lock-up cycling on and off.
Show the restHide
The other branch is the valve body: the control bores wear, and from then on the pressure cannot be held. A fault like that cannot be fixed with new solenoids: the seller's argument that "we replaced the solenoids" does not solve the problem on its own, and the symptom comes back after a few hundred kilometres.
What to check
- With a warm gearbox, at 60 to 90 km/h on steady throttle, watch for vibration or buzzing: that is the torque converter locking up
- Try it both cold and warm: a marked difference between the two points to valve body wear
- Watch for harsh 1 to 2 and 2 to 3 shifts and slipping under load
