As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE PERFORMING 150 HR INSPECTION A CRACK WAS FOUND ON THE UPPER HOUSING AFT RIGHT FOOT OF THE MAIN GEARBOX. (UPPER HOUSING TT 2336.7). REPLACED MAIN GEARBOX ASSEMBLY WITH A SERVICEABLE GEARBOX IAW SIKORSKY MM. A/C TT 3091.8 HRS. GRBOX P/N 76351-09600-042.