34 540 with M60 and 5HP30 transmission, the owner thought the noise comes from the 5HP30 transmission, maybe too low ATF or defective o-ring on the trans filter.
https://www.youtube.com/watch?v=RgqX...ature=youtu.be
https://www.youtube.com/watch?v=alFa...ature=youtu.be
Then someone told him: when this noise comes, remove the engine oil filler cap slightly, if then the noise is gone and there is a slight vacuum which pulls the filler cap on the valve cover, it is a defective PVC crankcase vent valve oil separator. This was confirmed to him also by a specialist from ZF, no problem with the trans. PCV Crankcase Vent Valve Oil Separator defective.