1998 1.8T 5spd....Does the trans fluid ever need replacing ? Can't find in service description.

Re: Audi says no, but..................
 

This is based on "normal driving conditions".

If you drive the car hard, race, or sport, you may consider changing the oil in the 5 speed.

Audi says no because it is a pain in the a**
 

But as was said below, if you work your tranny hard, you might want to change it after a while.

I changed mine in my 97, but...
 

It requires a special tool to remove the drain plug (3357 triple square driver, I think). You can get it from Zelenda for about $26, the trans holds 2.97 quarts of 75W90 (please double check, this is off the top of my head) The fill plug uses either the same as the drain, or a 17mm allen plug, depending on year. Mine had the 17 mm plug, so I welded a 17mm bolt to a bad 1/2" drive socket and went at it. I used Redline fluid. To fill, I used a funnel, and a long piece of hose coming up through the engine compartment (cheap garden hose by the foot works well, if it's not to large a diameter)

I changed it at 65K, and it was smoother shifting and better in colder weather. However, I lost second gear 3 weeks later. Not sure if it's just coincedence or not (I'm guessing it is)