Hi, it appears that Rock Auto has the steering gear for your truck: https://www.rockauto.com/en/catalog/gmc,1997,k1500+pickup,5.7l+v8,1158342,steering,steering+gear,7416
This is based on having a 5.7 liter engine.
Marc
Hello, I just replaced mine in my '98 Cheyenne K2500. In my case, I purchased a new one at the local dealer. It is a press fit with ridges covered in a red sealing material. I drilled the old one out with a drill slightly larger than the hole and increased the bit size until it spun out of the axle. I then used a socket to press it in.