Tightened the pinion nut... noise reduced. So it IS the rear and not the trans! Problem now is that I have no idea what I need to tighten that pinion...
That Marquis was local to me about a year to two years ago. It was on Craigslist with those pics. I had never seen one that color before this one but...
So much good space for cool gauges... but 1970’s GM and their MPG gauge! I remember reading about something similar in the owners manual of my mom’s...