I had a 2004 Newmar 5th and I believe the setup was the same.
Look at the end of the arms that connect to the outside of the slide out. (You need to go under the slide out) You should see slotted mounting brackets where the slid out attaches to the arms. You should also see a vertical bolt that has the head resting on top of the slide out arm. Loosen the mounting bolts in the vertical slots and adjust the bolt resting on top of the arm to raise or lower the slide room. I'm going by memory so look over closely to be sure you see and understand what I'm trying to say.
Make small adjustments (1 or 2 turns of adjustment bolt) and check operation often to make sure that your moving in the right direction. Retighten mounting bolts to lock in new position before operating slide to check.
Hopefully others can expand or clarify for your rig.
Randu