I'll leave the subject of tips on assembling the clutches to Gadge. Graphite on the clutch facings probably will reduce any noise the clutches are making, but will not fix the cause. Because you only get squealing when going forwards, not backwards, it sounds as if it is more likely to be belt squeal than clutch noise. Greenfields are very prone to slipping their belts in forward but not reverse, if there is insufficient belt tension. There is an automatic belt tension adjuster built into the idler pulley right in front of the clutches, under the seat. That pulley is on a slide, with a spring pushing it forward and a ratchet to restrict it to only sliding forward, to tighten the belt. If it did not have the ratchet the pulley would be pulled backward, loosening the belt, whenever the mower is driving forward, and it wouldn't ever go anywhere. However all ratchets unavoidably have finite steps between engagement points, and they also have to move some distance backwards to achieve full pawl engagement. Both of these effects reduce belt tension. The Greenfield's fairly elementary ratchet mechanism also has considerable friction, partly because it uses a spring steel leaf as the pawl, and this exerts a fair amount of pressure on the ratchet rod. So, when you get belt slip in the forward direction from time to time, you need to remove the seat and lever the sliding pulley forward slightly, listening for a click from the ratchet as it moves forward a notch. A beady-eyed critic would say that in Greenfields, the automatic belt tensioner is more semi-automatic than fully automatic.
