WVMKX

Hello, all. I have a 2007 MKX AWD. In late December I noticed some thick black fluid in the driveway where I park. I took it to the dealer and I was told that the PTU is leaking fluid. They quoted me around $1600 to replace the PTU. They said that replacing the seals could fix the problem, but they might find that the PTU needs replaced when they open it up. The service manager told me that when they checked the PTU fluid, it seemed to be overfilled. My question is, is there any risk to putting off replacing the PTU? Is there any risk of damage to the transmission if I put off this repair? The reason I ask about the transmission is that I've seen where there can be a seal that leaks between the transmission and the PTU. It made me wonder if the leak goes in both directions, and could contaminate the transmission fluid. Or could it cause the transmission fluid to become low enough to cause damage. Can I put off the repair to the PTU until there are other symptoms than just a few spots in the driveway? Or, could I just add fluid to the PTU periodically? Or should I schedule a replacement soon? If anyone has any advice on what is the best thing to do in this situation, it would be much appreciated.