On a 2004 Ford Transit, the speedometer cable isn't directly connected to the gearbox in the same way as older vehicles. Instead, the Transit uses a
Vehicle Speed Sensor (VSS). This sensor is mounted on the gearbox, but it's an electronic sensor that sends a signal to the instrument cluster, not a mechanical cable. Therefore, you won't find a speedometer cable.
You'll need to look for the VSS on the gearbox itself. Its location varies slightly depending on the specific gearbox type, but it's typically found on the side of the gearbox casing, near where a speedometer cable *would* be on an older vehicle. It's usually a small, round sensor with a single wire connector.