Kathy,
Do not oil or grease any of the nylon ( plastic ) bits. They can react with the oil and expand. When that happens the bobbin parts will bind up.
Also for the top shaft bushings stand the machine on it's end and oil them so the oil will soak down between the shaft and bushings. Those were oil impregnated bushings and the original oil is long dried out. This is where the Tri-Flow oil really shines.
There are also bushings on the presser foot shaft and needle bar.
Joe