[ss3011]

Two ways to cure this problem. first is to make sure the converter bushing is in good shape and has the proper clearance to the converter neck, second is to open up the drain back passage that vents behind the converter seal . A 200 has a cast iron pump and the press fit for the seal is pretty robust. The 4L60 had an aluminum pump, and had a problem losing the converter seal , so a seal retainer was designed that pressed on over the seal to retain it, due to loss of press fit as the aluminum pump expanded as it heated up. Cast iron pumps don't usually have this problem. Your problem is probably caused by excessive leakage getting into the pocket behind the seal, so that clearance between the converter neck and the bushing is probably where that leak is coming from. Let us know what you find !