I've seen a few 00 with an everette trencher.
If the hyds section didn't raise your diffy, then I'd say the hyds were a bit low on oil. sump holds 2 gallons normal fill, and will hold an extra if needed for external cyls. In practice, with only the 3pt being used.. it could get away and still pickup with probably a gallon in there.. thus may have been low.
if both sumps had utf in them, then the mixing would not be an issue.. but if one sump had utf, and one gear oil.. or worse.. if one sump had hyd fluid and one sump had gear oil, then the hyd fluid could potentially contaminate the gear oil. again.. if hyds level was artifically low.. probably not an issue.
lastly.. if the diffy was overfilled, and the seals were exceptionally good, then you would not notice an overfill in the diffy.
the fact remains unchanged though that snatching that shaft allows the hyds to drain into the diffy.. no doubt about it... you can look straight intot he open tail end and verify, plus look at the exploded parts diagrams. I'm not making this up. I've probably had every pto out of my fords from everything under my 4600 and down..
soundguy