I recently installed a Series III in my 98 Firebird. A week later I hear a slight tap. I initially thought it was transmission gears because the transmission was very low when I checked it. I filled the trans and drove about 80 miles home. The noise is much louder now. I cannot hear it on cold starts. I can only hear it when the engine gets around 160 degrees. The knock goes away around 1500 rpm in park, but is constant when in drive. Two shops say litter noise and two different shops say crankshaft. Ideas anyone?