Careful using lubrication on bulkhead seals. They are not designed to be used that way. Best case it won't do any harm. Worst case it can temporarily patch a defective seal causing a potential leak in the future. Be careful when tightening because the lubricant will reduce the torque giving you the perception to keep tightening which can cause the seal to slip and shift out of position. If you have the time I would pull the sump and sump extension out and water test in an open area so you can see where the leak is coming from and address accordingly. Good luck!