Bearfoil
I think you misunderstood what I was attempting to say, perhaps I wasn't clear.
Indeed, the fan-LPT shaft is inside the IP shaft. The rigid coupling between the two is underneath and between bearings #3 and #4
as a reference point only. I said nothing about oil.
The IP shaft rigid coupling is located just aft of the #4 bearing but forward of the #5 bearing
for location reference. It is this coupling that I think is cause for wear concern by the safety folks. Again, I did not mention oil.
Both couplings are axial spline couplings.
The only oil I mentioned is that which came out as a result of the stub pipe which failed and went somewhere it shouldn't have. This oil pertains to the #6 and #7 bearings that reside between the IPT disc ID and the OD of the IP shaft.
Hope this is clearer to you.
Turbine D