What may of happened the cog wheel is offset in one of the rail holes of the two rails under slide.
What you may need to do is release the torque nuts and with help from others push in the slide.
In QT's 1 & 2
you will find Newmar slide information for older coach slides, I believe you have a living room slide.
With the slide already up the ramp and setting on main floor you will have access to torque nuts in compartments below. You need crows foot to release nuts and they have two torque values 125 and 145 lbs.
If you not capable of doing the work find a good Newmar dealer call Newmar
All the links below in my signature have information for your Newmar.
I am located in the Newmar forum.