Noise when clutch pedal is depress

Landrover defender 130 td5 after i have replace the clutch kit and thrustbearing when i depress the clutch pedal there is a noise sound like gears running with out oil but with the clutch pedal still depressed and selecting 2nd gear the noise go away but when i select any other gears the noise comes back even when in neutral but when i release the clutch pedal the noise is gone can it be something in the gearbox or the spigot bush that cause that noise. Thanks Max.