tripleR,
yes it has the hydraulic shuttle
We used a synchro shuttle for 12 years before trading it in on the M8540 and love the hydraulic shuttle. Even though we have had it for a few months, I occasionally find myself hitting the foot clutch though; old habits die hard.
we have a jd5520 with a power reverser and i sometimes hit the clutch for the first couple min of operation because im used to shifting the 2555. and even worst than that when i get in the 4520, which has a hydro trans, after running the 2555 i sometimes find myself reaching for the shifter