Scope mount has some slack in vertical motion

Hi, I’ve noticed recently that my Celestron NextStar 8SE alt-azth mount has some slack (or slop) in the gears only in the vertical direction. Wonder how I can remedy that situation? Do I need to bring it to Astronomics for a work-over or is there something else I can do? Any advice appreciable - thanks.

Here are a few resources to check if you want to try yourself:

Thank you so much Tom. These will likely help a lot.