We have had a reoccurring issue on an otherwise healthy 9600 combine. The cooling shaft that connects to the engine via a harmonic coupler keeps failing right against the coupler itself. The welded bolt flange keeps breaking in the same place each time. The engine runs fine without any noticeable vibration or sound at all rpms. The rest of the cooling assembly seems fine. Bearings are smooth and tight. Assembly can be turned by fingers alone in a smooth and quiet manner. The screen cleaner is also smooth and quiet. It appears for this to break in this location there must be some sort of flexing going on that currently isn't noticeable. Two things are lightly mentioned online but don't seem to apply to this after review. 1. That the outer engine bearing is starting to go and this vibration is failing the connection, or 2. that the engine itself has settled into the frame and when on high torque load specifically, tilts ever so lightly but enough to fail this joint.
Does anyone have any other ideas? Would greatly appreciate any other ideas or insights that we have not identified so far. Or, even if you have had the same failures and how you isolated the cause and resolved it.
Its an expensive part an it takes the best part of an hour to replace this with another failure coming within the same round on the field. So very stressful and confusing at the same time.
Any help is very much appreciated.