My Bentley Service Manual says that there is no prescribed ATF change interval for this transmission (5-speed automatic model 01V) just that it must be checked after leaks are found and corrected.

My Haynes Manual says the interval for this box is 40,000 miles or 4 years.

The car's original Service Booklet says interval is 60,000 km (37,500 miles) EXCEPT 5-speed box, but there is no interval given for this box.
The only other interval mentioned is 30,000 miles for the A6, according to the engine/gearbox combination.

My question is, should I change the fluid or not? The transmission works perfectly, it is very smooth and quiet.

The car has now done just under 30,000 miles from new, but I have no record of the ATF ever being changed.

If I have to change the fluid, it seems I need a little tube with a "hook" at the end to fill via the plug on the bottom, while checking the fluid temperature is between 35º and 45º with my VAG 1552.

I can easily fabricate this tube, if someone has one, can you please tell me its O/D and I/D?