As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IMMEDIATELY AFTER TAKEOFF, THE MAIN LANDING GEAR WOULD NOT RETRACT / REMOVED AND REPLACED HYD SYS 3 RESERVOIR IAW CRJ700 AMM 29-12-30-000/400-801-A01-PSA. PERFORMED EXTENSION/RETRACTION OF THE LANDING GEAR IAW CRJ 700 AMM 32-30-00-865-801. OPS CHECK GOOD AT THIS TIME.