Yesterday, after I changed my transmission fluid, I was told that I have my first real issue. A rear main seal leak. It's not bad, but were I to repair it, it would cost $2,000 at the dealer, and maybe a little less at my mechanic's. The dealer told me this is a 12-hour job. My mechanic also told me this could have been caused by debris in the oil that made it past the filter. Since I run long OCIs (Oil Change Intervals, currently 26,000 miles), that may have allowed something to make it past the filter. He suggested I look into bypass filtration again. Long story short, I once looked into that to increase my OCIs but the cost difference wasn't worth the trouble. Since the filter on the bypass system is finer than the standard oil filter, it may be worthwhile just to avoid problems like this down the road. I don't plan on fixing the leak right away, only when it's necessary. Just in case I run into another issue down the road where the transmission has to come out anyway.