Hi @oldman23
Welcome to HP Support Forums. A really great platform for posting all your questions and finding solutions.
I understand that the Gear set came off from the Shaft. Usually printer parts of not replaceable.
I would request you to contact our Phone Support for Service Options.
Step 1. Open link: www.hp.com/contacthp/
Step 2. Enter Product number or select to auto detect
Step 3. Scroll down to "Still need help? Complete the form to select your contact options"
Step 4. Scroll down and click: HP contact options - click on Get phone number and phone number appear.
Thank you. 🙂
KrazyToad
I Am An HP Employee