[Superman]

Sure, if it is pinging then you need to solve the problem, by using higher octane gas (I only use premium in the engines I care about), or by retarding timing just a skosh. Is your timing advanced beyond factory spec? If not, then pinging is not likely the problem. Or at least, premium should clear it up. Unless there are atrochious carbon deposits on your piston tops and valve heads.

No, I still think the more likely thing is tranny noises. Let me ask this: The noise, is it gravelly and grinding but not snappy? Pinging usually has a sharp edge. A crackling quality. Snapping. Whereas tranny grinding is just rattly. Another question: Has your shift coupler been re-bushed. Factory shift coupler bushings have an oblong bore that helps prevent tranny noises from entering the cabin through the shift rod. Replacement bushings have a round bore that insulates poorly. My car has the round replacement bushings, and I get plenty of crunch, grinding, rattly tranny noises. Particularly at low rpms under load. The shift coupler is located under the plate on the tunnel between the feet of your rear seat passengers.