define pouring please. Are we talking a puddle that runs out from under the truck or a 1/4" stream or it leaves a 1' puddle when parked.
The torque converter seal on the 4r100 and e4OD (you have a 4r100) is prone to leak if it's gotten too hot because it gets brittle with heat. there are aftermarket seals that take the temp swings far better.
Though dave points out a fact that if you've poured out too much fluid over too long of a time you may have further damaged the internals of the transmission that would necessitate a full rebuild not to mention that if you're still on the OE trans with your mileage you're a bit overdue by most accounts for a rebuild. The reality is that the seal is a sub $20 part with a healthy labor bill and many shops will add the other stuff on just to cover their rear if it is something else and then the labor is not 99% of the bill.
