Think I broke it

Sorry it's taken so long to get back but it's harvest time and I keep getting called out to repair combines. Any way here is the photo of the adapter, a little dirty, but it's LR what can you expect

Had time today to get it bleed an started, No drive to rear wheels.
I put it in two wheel drive, put it in first gear let the clutch out and nothing
prop not turning, I then put it into 4 wheel drive clutch out and drive to front wheels in high and low.
I'm thinking along the lines of a stripped or broken rear output shaft,
any other ideas.