Clutch withdrawn sleve seal in suffix F gearbox

[Aaron IIA]

I am curruntly rebuilding a suffix F gearbox. The clutch withdrawl sleeve in these gearboxes differs to those of earlier boxes. Instead of having a spiral cut into the input shaft, there is a seal inside the clutch withdrawl sleeve which runs against the smooth input shaft. I am having difficulty in determining how this seal is removed. My manual only shows the earlier, more common spiral version. Has anybody ever changed this seal before?

Aaron.