The rear end on my 89 535 with 165k on the clock is starting to whine very loudly, especially around 60 mph. I took it to my mechanic who told me that it sounds like a bearing going out. Since I'm already dumping $800.00 into a head gasket repair job, I really don't feel like replacing the rear end on it! Has any one had the same experience? Will Red Line quiet it down? Any suggestions would be appreciated.