Knots

I have a 2004 Scag TT model STT61A-27CH with a 61inch deck that has a deck adjustment issue. Page 24 of the owners manual says" loosen the serrated flange hex nut and move the bolt up or down to adjust the deck". As near as I can tell, there is no serrated flange hex nut and no slot to move it up or down.
Has anyone else run into this problem while trying to level the deck left to right?
Any info would be greatly appreciated. Need help!

Thanks

Knots