first tiptronic not nice

[barneysbmw]

i think there is a problem with my gear box my e46 has 100.000 miles on it the tip box changes smooth ok but if i put the foot down it acts as if the clutch is slipping but there is no clutch do i need a new gearbox or torque converter or just change the atf fluid

[Hootie]

Covered many times before:

here
here

[barneysbmw]

so how can i tell if its the gear box or the torque converter the car drives ok and changes gear fine but when i put the right foot down the revs shoot up but the car takes a while to start picking up