As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PRE-FLIGHT INSPECTION FOUND MOUNTING PADS WORN BEYOND LIMITS IN BHT 407 CR&O MANUAL. ONE EACH DOW ALIGNMENT PIN BROKEN. FURTHER TEAR-DOWN REVEALED HIGH GEAR BACKLASH AND SCARING OF THE GEAR TEETH. POSSIBLY DUE TO LOW OR ABSENCE OF OIL AT THE SAME TIME. HIGH VIBRATION CAUSED GEARBOX TO LOOSEN UP.