Hi,

It's a manual 300tdi and I guess it's time to change the transmission fluid. How do I find the following:
1. Filler plug
2. Drain plug
3. Filter

In the very limited light that I can get underneath the thing, I don't see anything resembling a plug.

and a silly question: is there a dipstick for measuring the level or there's one only on an auto box?

no filter for gear box you can change its internal filler and drain are on prop side of box filler t55 torx bit, drain 11/4 spanner size or 32mm