Usual suspects:
1. The two bolts that secure the bottom of the cover that are accessed from inside the pan. A fix for this is to tap the bearing cap, and drill the tapped holes in the cover bottom so it can be tightened after the pan is installed.
2. A groove in the vibration dampner which causes the seal to leak and fail. You can use a speedy sleeve to get a smooth surface and positive seal in this instance.
3. Make sure cover is properly centered and indexed to the bore for the vibration dampner.
I had trouble locating the threads mentioned above, so here is where to start looking.
