(sorry can't remember names that well)
Yes, there is a op code for trans fluid and filter, with a small caveat:
The code listed is for model designators (you probably won't recognize these types of designators) C1, C2 and C3. A C1 is a C220, which was made only with a 722.4 trans. A C2 is a C280 with the 104 motor, had either a 722.4 or .6 depending on year, and a C3 is a C36, also available with either the 722.4 or .6 depending on year. In the operation fiche, there is no differential noted between the type of transmission the car has. I tend to believe the intention was for the 722.4 transmission, but again, the model indicator "fits" either model (either transmission type). Like a dumass, I didn't look for the C230 like yours, though, so I will repost on Monday my findings. For some reason I thought you had a C280, not a 230. I like the naturally aspirated C230, nice running cars. The (warranty) labor time for this job is .8 hour on a C1, C2, C3 car.