I build transmissions for a living and deal with the leaks all the time.
The shifter shaft seal is a common place for leaks to occur.
It is relatively easy to fix.
Disconnect the linkage from the shaft, purchase a new seal and the seal remover/ installer tool at your local auto parts store.
The tool has a tapered pipe that threads into the old seal. You then use the bolt in the kit to pull the seal/ tool out of the case.
Then use the other part of the tool to tap the new seal in place.
As for the pan gasket leak, its probably a warped pan rail due to over tightening.
You can remove the pan and straighten the rails and reinstall with a new gasket.
If your pan doesn't have a drain plug, you can add one while its off.
There are kits available to do this as well.
