I want to replace the oil in my tranny. It's a ZC motor and I believe the Tranny is the S3? What Do you guy use or what should I use. I have the factory service manual and it say 10w-30 to 10w-40? I have never used regular oil in a tranny! Alway synthetic gear oil or syncromesh. But what is right? Here's the Service manual Recommendations: API Service Grade: Se or SF SAE30, 10w-30,10w-40 or 20w-40 grade oil. Thanks!