I have an early TR4 A type overdrive tranny (CT5452) from my early 62 TR4. My TR6 trannies have a vent hole on the front of the top cover. I don't see one on this tranny at all. Is there supposed to be a vent hole on these? I would think there would be. Thanks, Jim Henningsen Ocala, FL 62 TR4 75 TR6