C4 6-Speed Transmission: Shifting Problems?

Hello,
I'm having trouble shifting gears; the gear lever travel is very long.
For example, when shifting into third gear, you get the feeling that the shift linkage is sliding into each other, and only engages on the last 5 mm, causing the gear to click into place.
However, this gap must be located within the transmission, as the shift rods and lever are actually firmly attached to the shaft.
Does anyone have an exploded diagram of the gearbox housing? Or any tips on how to remove the actuator with the gearbox installed?
'Thank you!'

(To Rainer: I'll be sending you the blink codes for an AAT soon!)