I wrote up a DIY about these 63-66 C10 steering columns. It has 4 parts. Depending on your situation, you may need to disassemble and inspect the whole column! Do not be intimidated. It is not difficult to do and once it’s back together you will have full confidence that it’s gonna be ready for service.
DIY Steering Column LINK

1965 Chevy C10 Shortbed 1/2-Ton Stepside
Truck College
In the Stovebolt Gallery
In the Project Journals Forum
The Build BLOG on Weebly
T5 Transmission Build page