As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING THE TAKEOFF ROLL EXPERIENCED MEDIUM TO SEVERE NOSE WHEEL VIBRATIONS. BEGAN AT APPROXIMATELY 30KTS & DID NOT STOP UNTIL LONG AFTER GEAR RETRACTION. ACCOMPLISHED FIM 32-51-00 FIGURE 403. R & R STEERING METERING VLV IAW AMM 32-51-04.