A904 has reverse no foward

Sounds like you've found your problem. It could also be the reaction shaft sealing rings leaking. They seal the port to the front clutch so if their not sealing it'll leak similar to a front clutch leak.

The throttle pressure (kickdown) linkage just needs to be hooked up so that when you floor the pedal the linkage pushes the lever down on the trans either all the way back or real close to all the way and when the carb is at idle the lever down on the trans is forward almost all the way if not all the way forward. In other words the linkage should cause the trans lever to move in sync with the carburetor throttle