Dys 4500 deck

I have a 2006 dys 4500 26 hp 54"cut mower. With the deck fully raised the front caster wheels of the deck stay on the ground. With the deck in the lowest setting the mower will just spin tires. Is there a way to adjust the height of the front of the deck? It's a pain to load on a trailer and gets easily hung in ruts/ditches/ uneven yard. The only adjustments I've seen are on the arms that lift the deck or adjust the cut height. Any help/advice is appreciated.

Dys 4500 deck