sluggish 727..

Old rubber lip seals can cause the odd drive problems (Possible clogged filter also)
Converter drain back is usually the pump bushing letting the fluid run back into the trans, and since these only circulate fluid in neutral in thier stock form it takes a bit in neutral to fill the converter back up.

When the rubber seals get hot they get softer and will end up flaring out and sealing.
This is a sure sign of immenent failure.