I'd like to find out how widespread this problem is and what solution(s) there are, if any, as well as whether it is just A6 2.7T or other Audi cars with Tiptronic gearboxes. Perhaps this will help affected owners overcome the "no fault found", "operation normal and per manufacturer's spec." response from some dealers.

One likely cause may be a solenoid valve seal that was improperly installed in early cars. It has also been suggested that the gearbox control unit software may have developed a glitch. At this time I do not know of any confirmed causes.

(PLEASE NOTE: I am not connected with Audi, the motor car trade, legal trade, consumer organization or any trading standards organization. If the Forum Moderator feels this survey is inappropriate for any reason, please delete it. An email note to myself would be appreciated. Thank You.)

PROBLEM:
a) A jerk (moderate to severe) can be felt upon acceleration (moderate)from a slow turn. Gearbox is typically in second gear when this happens.

b) Same jerk as in item a) above but upon acceleration (moderate)from rolling stop when gearbox is in second.
Some common rolling stop scenarios: slowing down for red traffic light which turns to green before full stop; slowing to enter a driveway.

FORUM REQUEST:
If you have experienced the above mentioned jerk phenomenon please post the following:

MODEL/ENGINE: (1.8T, 2.8, 2.7T, 4.2)
YEAR:
GEAR IN WHICH JERK NOTICED:
APPROX. WHEN FIRST NOTICED: (odometer miles)
SOLUTION IF KNOWN:
ADDITIONAL COMMENTS:

 

Most Tip drivers here have noticed it. The consensus seems to be that it's caused by driveline "windup" that catches the tranny a little off guard as it shifts. As I understand it, because the quattro system (found on most cars here) is mechanical, it can contain its own inertia. so that when you change speeds in slowing down, there is a "ripple effect" of slowdown from the wheels, through the drivetrain to the transmission, which is amplified because the quattro is more complex than a normal drivetrain. when this wave of speed change hits the tranny, it might do it at an inopportune time and cause a thunk.

I hope this was clear, I'm not an engineer or mechanic, and my description was based on my interpretation of what I've read here, and is by no means authoritative.

To answer your original post, I experience the thunk you describe under the exact circumstances you describe. I have a 2000 2.7T Tip I bought the car with 22k miles on it and it has laways done this. I assume it was/is normal.

 

Torque Converter Lock up! This is a 'Feature' on all Tips!

 

No that's not it, TC does not lock/unlock at such low speeds/low gears

 

depending on TBW application and Tip state. (Ditto wife's 1.8T) This issue much discussed here over the years.

 

definitely a second gear throttle roll on problem. The dealer did a throttle adaptation and it made the problem less severe but the next few days will tell if the problem is reduced to a minor annoyance or if I am going to get riled up about it.
Mine was so bad that twice when I pushed the throttle down fast while slowly rolling the car almost tore itself apart when the power surged in a snap fashion.

Car is a 2001 S4 2.7T with 18K miles and noticed the problem about 500 miles ago just before Christmas in cold weather.

Dealer wants to solve this problem just like me.
I will keep you updated on what transpires.

 

My "jerk" led to gearbox replacement. Thanks for the explanation.

 

Mine just started doing it. 6 months and 18K after delivery.

 

would apply to slowing down, when the transmission is downshifting. Is it possible that the clutch packs are unloaded? The first/reverse clutch pack is just beginning to be engaged, while at the same time the 2nd/3rd clutch pack is releasing. The quattro AWD (the whole drivetrain system) has inertia while the tranny is basically in a no load transfer condition. Now, apply the throttle, the two clutch packs have to catch-up, the computer has to select a clutch pack to engage.
This could lead to very noticeable shudder throughout the drivetrain, transmitted to us the drive.

 

yeah that happens to me also.... always wondered what it was.