I'v cracked a case before in a different car. It had a huge leak compared to this. There is no huge leak on the starting line or the track officials would have told me. I get on the trans brake in the shop and no leak. I know its on the brake longer at the track and they havn't said anything to me. Its down about 1/2 litre in 6 or 7 passes. I only notice the leak after a pass. The car is a 69 back half Chevelle with a front motor plate and stock trans mount. It runs 10.0 at 135mph. I'm hitting nuetral after every pass. Could that have something to do with it? I'm useing Dextron 3 fluid.