Have you checked your timing? If the timing chain is original, it should be replaced. They tend to stretch out and that throws the timing off, which could cause the pinging. As far as the oil goes, is it all over the top of the transmission or just underneath it? With 170,000 miles on the clock, the engine will probably need rebuilt soon.
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1989 lx notch
89,000 miles
5-speed, bolt-ons, 3.73, TFS TWs, TFS Track Heat, TFS Stage 1 cam
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