Hi all
The subject of what clutch can only be checked by visually confirming if there are holes in the clutch housing. RO has checked with the data and found this engine was not supplied with a clutch housing with holes. That said you simply can follow the manual as to if you used leaded fuel enough to warrant doing the check at 600 or going to 1000.
It is important to point out that I have never seen a gearbox run past 400 to 600 hours that is not in need of gearbox reshim. The check for this is the friction check shown in the MML for the engine. Simply speaking if the gearbox rattles at idle speed get it fixed before you damage a lot more parts inside. At that time when it is apart the clutch can be inspected.
Within the MML there is also another test, the overload clutch test. This should not be confused with the friction test as they are completely different checks and serve different purposes. Within the manual it is discussed and while it primarily is for any slipping of the overload clutch, as in wear or incorrect oils, it also helps in this case. When the clutch system fills with lead the disk plates internally begin to plug with lead paste from the fuel. Over time this will INCREASE the value. At some point they then become just a spinning disk of solid parts and no longer absorb the vibrations and torque loading changes.
Cheers
