We replaced both of mine this past summer, 2008 230 Wake (dual engines). Mine were not leaking but we had about 230 hours on the boat. I'm glad we did because there was some pitting on both. When you do, make sure you replace all the corresponding parts like the boot and etc. while it is disassembled. 67 hours is nothing...unless your accordion looking boot over the drive shaft appears dry rotted, I agree with POPPS above, wait. And if it doesn't start leaking after a few summers depending on your hours used, tackle it or have it done as a maintenance item. It is an enormous undertaking...at least on my boat it required removing LOTS of other components to access it...I hired a driveway boat mechanic I know who allowed me to assist to learn.