As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 3968 - CREW REPORTED AFTER TAKEOFF THEY RECEIVED LANDING GEAR AIR/GROUND FAIL AND FEAR WOULD NOT RETRACT. AIRCRAFT RETURNED TO ORD AND LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REMOVED AND REPLACED LT MAIN LANDING GEAR WOW PROX SW NR 2. OPERATIONAL CHECK GOOD. REMOVED AND REPLACED LANDING GEAR CONTROL LEVER. REMOVED AND REPLACED CARDAN JOINT ON RT MAIN LANDING GEAR. FCF PASSED. AIRCRAFT RETURNED AT SERVICE. (A)