As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LANDING GEAR LEVER WOULD NOT MOVE TO THE UP POS AFTER TAKEOFF. WE PINNED THE GEAR FOR GEAR CONTROL SYSTEM TEST FOR VERIFICATION. AND REMOVED THE COVER FOR THE GEAR HANDLE BOX. FOUND A SPACER ACCOMPLISHED LANDING GEAR CONTROL SYSTEM TEST. OPS CHECKED NORMAL.