Third Failure Automatic Box 01m Golf 4

Hello friends, I need your advice because it is the first automatic box that I have ever played.
What happens is that when the third is practically engulf there is no traction, as if the clutch would be open.
There are no error codes in the trans car, I have disassembled the valve body, I have cleaned it, the solenoid resistance values ​​seem to be well. I have changed the filter and the ATF, but it continues to fail the same.
What I have seen with the vagcom, with the car in progress, (car trans-means block), which in the first and second march, which are also, after giving the speed, the cheriff's dazzling values ​​fall progressively to very low values, but when they engage the third these values ​​are fired until 1900.
Someone could give me a clue of what is happening?