Anyone Heard of This? 3rd-4th Change Problem

[Dave80s]

Hi, can anyone help with my gearbox issue, my car is an S8, 98 model (Pre facelift S2).

The tiptronic box is fine except for one thing, between 3rd and 4th it changes up really late - at about 2400rpm.

All the other changes are below 2000rpm (when cruising). I can override it by doing it myself but as you can imagine I don't want to have to do it all the time.

Any ideas?