So the pentosin was for the tranny oil. Advance lists it for $19.99/ quart. The fluid chart at Advance said 8.5 for transmission fluid also, as well as the engine oil. I think their chart is off. I mentioned the differential because I plan on changing the rear differential oil, while I'm under there. I have read some threads on here that suggest it be changed at 50K miles. I am the second owner and not sure if it was ever done. Advance shows a 30K mile service for the rear end/differential.