Gearbox installation

At 1045hrs I noticed a slight vibration about 1/2 hour into my flight. I have a 912ULS that I've been flying for over 16 years. It did not change during the next half hour and was not noticeable on the ground. The next week the vibration started again after about 15 minutes. It was very light and almost unnoticeable but I was concerned. I called Lockwood tech assistance number and was told I should send it in for inspection. I had it inspected at 400hrs because I learned that my Warp Drive prop was too heavy. My new prop is of the correct weight. After inspection my gearbox required a thorough overhaul and I was told I did real good by noticing the slight vibration. Now I'm about to reinstall it. I have to replace the drive gear on the crankshaft and I'm looking for the plug on the case to remove to install the lock screw so I can remove the nut holding the gear. I think it's right beside the oil filter but I'm hoping someone can verify that and provide some guidance. 

Thank you,

Alan