I decided to install a new clutch release bearing before reinstalling my engine and I see some have a grease fitting on them. What does that apply grease, the bearing race or transmission input sleeve? How would you ever access the grease fitting after installation anyway? Another question, do I need to apply a thin film of grease to the transmission input shaft? Would you go with a National or SKF bearing? I've replaced this bearing before and found the new one was defective while the old one was fine. I do not want to go through that again.