[Oz-jeep]

Hi

I have a manual 2000 tj, when driving in 3rd 4th or 5th I have a noise like an old machine gun. The noise is constant no matter what gear I'm in but increases/decreases with relation to speed. If I ease off the throttle the noise stops. The noise also stops if I put it in 4hi. No noise when using 1st or 2nd or when out or gear or stationery. The noise appears to be coming from the L/H side of the jeep around the transmission or forward towards the front axle.
Any ideas please as I'm new to the jeep scene

Thanks