[thstone]

I am going to venture to say that the CEL and the oil leak are probably not related.

And if they are related, then damage may already be happening and there's not much you can do about it except stop driving the car and think about engine options.

With that being said, there are two likely causes of the oil leak - rear main seal and IMSB seal. Some people have tried to snake an inspection scope into the bell housing but its nearly impossible to see much. Thus, the only way to determine what is leaking is to remove the transmission.

Of course, once you've paid the labor to remove the transmission, you're mostly committed to repairing whatever you find and its easy to replace the IMSB since its literally sitting right in front at this point. But this means that you'll likely be into the job for several thousand.

The CEL could be almost anything but they are most often emissions related. That doesn't mean that it should be ignored as some CEL's are critically important to rectify as soon as possible (like a misfire). Others can be ignored but you'll have to get the CEL code to determine a prudent path forward.

If the CEL and the oil leak are related, then the oil leak is likely from a failing IMSB and that means that the engine might already be compromised. The next steps would be to immediately check the oil filter and the sump for metal. Then go from there.

Start by finding out the CEL codes and posting them here. Someone will provide info and recommendations for repair.

In the meantime, you can live with the oil leak for awhile but eventually it will get to the point where you'll have to remove the transmission to fix the leak. That might be the time to replace the IMSB and eliminate that worry, but the choice about replacing the IMSB is yours alone.