904 tranny problems

How high does it rev before you start moving? Does the car have a tach installed? If you're certain there is enough fluid in it, pull the dipstick & smell the fluid. Does it smell burnt? Like burnt toast or burnt popcorn? If so get someone who is familiar with automatic transmissions to look at it. It may be time for a rebuild if it's slipping. As another member pointed out, the problem is not likely the kickdown/ throttle pressure linkage adjustment. It won't cause it to slip when pulling away. It will however, cause it to fail if not properly adjusted later on.