Technical question:

For over a year now (maybe longer) I've noticed an annoying "blip" in the revs at around 2k (maximum torque I'd assume).
I've had a gearbox flush, which initially masked the blip, but it has gradually returned.

Slight inclines seam to trigger it, with a 500rpm surge in revs but no increase in speed.

It seams to be getting worse, as my usual " little blast up the hill" every morning seams to be now all revs and no go unless I really toe it, and then it's mental...

The characteristics of the engine/transmission has just changed, with less low down torque with now more revs to make it go, rather like a petrol engined car.

The car is BAS tuned which my dealer says is most likely the cause.

I've done some searching on the web, and found this relating to torque converters:


Lock-Up Clutch Mechanism
The Torque Converter Clutch (TCC) is hydraulically controlled by an electronic pressure regulating solenoid (EPRS4) which is controlled by the TCM. This allows the torque converter to have three states of operation as follows:


Fully engaged
Controlled slip variable engagement
Fully disengaged
The TCC is controlled by two hydraulic spool valves located in the valve block. These valves are actuated by pilot pressure supplied via a solenoid valve which is also located in the valve block. The solenoid valve is operated by PWM signals from the TCM to give full, partial or no lock-up of the torque converter.

The lock-up clutch is a hydro-mechanical device which eliminates torque converter slip, improving fuel consumption. The engagement and disengagement is controlled by the TCM to allow a certain amount of controlled 'slip'. This allows a small difference in the rotational speeds of the impeller and the turbine which results in improved shift quality. The lock-up clutch comprises a piston and a clutch friction plate.

In the unlocked condition, the oil pressure supplied to the piston chamber and the turbine chamber is equal. Pressurised fluid flows through a drilling in the turbine shaft and through the piston chamber to the turbine chamber. In this condition the clutch plate is held away from the torque converter body and torque converter slip is permitted.

In the locked condition, the TCC spool valves are actuated by the electronic pressure regulating solenoid (EPRS4). The fluid flow in the unlocked condition is reversed and the piston chamber is vented. Pressurised fluid is directed into the turbine chamber and is applied to the clutch piston. The piston moves with the pressure and pushes the clutch plate against the torque converter body. As the pressure increases, the friction between the clutch plate and the body increases, finally resulting in full lock-up of the clutch plate with the body. In this condition there is direct mechanical drive from the engine crankshaft to the transmission planetary gear train.

I'd like to ask,

Is the same torque converter used for the TDV6, TDV8 and 4.2 s/c? RRS gone
Audi SQ5...Gone Audi Q7 S-Line 240 3.0TDI Gone
Audi A6 Allroad Sport 270 3.0TDI

I've just performed a t/c stall test. (It was cold mind you, which is when the symptoms are least obvious)

It held at 2k rpm so that part of the t/c is working fine.. I'll re-test when its warm

I'm assuming the variable engagement is my next concern RRS gone
Audi SQ5...Gone Audi Q7 S-Line 240 3.0TDI Gone
Audi A6 Allroad Sport 270 3.0TDI

awd man wrote:

I'd like to ask,

Is the same torque converter used for the TDV6, TDV8 and 4.2 s/c?

http://www.ebay.co.uk/itm/DR-TRANNY-LUBEGA...0510836237

Some people on the D3 forum have had success with this additive, just a passing thought.