Ours at 133K miles had a rear differential leak (just a couple drops on garage floor, saw it immediately and the left rear axle had seepage where it connects to the drivetrain, a seal on the left axle and axle nut needed to be replaced. ~$1,200 for Lexus to repair (almost all labor, the seals cost very little) - and at that time they also changed the differential fluid, which I don't think it had been done at any time prior. Just thought I'd mention for those who stumble across this prior post....
