I learned, after I had my torque converter in the C4 and the C4 bolted to the engine not to use regular multipurpose grease on the torque converter shaft seal. Use a trans gel. The multipurpose grease can prevent the seal from totally sealing and can allow a leak. So a transmission shop on YouTube said, for what it's worth- sounded reasonable to me. Unfortunately I had taken the advice of a mechanic and used moly mulipurpose grease. I'll see.