I discovered recently that most auto parts stores list the wrong size rear transmission seal for the '70 Riviera. (most likely for '66-'70 Riv, and other big buicks) The one that most stores list has an I.D. that is way too big. Long story short. Go to NAPA and get #16871. I don't know why I bother going to places like Advance Auto, Checker etc. for this kind of thing. I always end up at NAPA in the end anyway.
