Randy, I've seen that same leak, twice. One was the vertical shaft model (285), the other was the horizontal shaft engine very similar to your 425, but it was in a Kawasaki Mule. I can't say that area is prone to leak, but sure seems that way. The replacement gasket may be a better material. The old ones just seemed to turn to mush in that little curve.
Look up the parts on jdparts.deere.com. It isn't too bad a job. Once you pull the pump and crankcase cover, you will want to replace all those gaskets, the "O" rings in the case, and the bottom seal. A new coolant pump is good insurance against doing most of the same job again later. If your machine is old enough, you might find the plastic geared camshaft in there.
I highly recommend purchasing the manual for liquid cooled Kawasaki engines that matches you model. If you keep running a L/C Deere with a Kawasaki, it will get you out of a lot of problems.
tommyhawk