As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI OUT, ALL HYDRAULIC FLUID FROM SYSTEM 3 WAS LOST. AIRCRAFT RETURNED TO THE GATE. THE RIGHT HYDRAULIC HORIZONTAL STABILIZER TRIM BRAKE MOTOR CASING WAS FOUND CRACKED. REMOVED AND REPLACED TRIM BRAKE MOTOR AND ACCOMPLISHED LEAK CHECKS AND SERVICING.