Next time, when you put the converter in the transmission, push and spin until it "seats" 3 times.. and whoever told you that a pump costs $50 is full of it. I paid $150 for a rebuilt pump on several occasions. Most transmission shops will sell you a seal, o-ring, and pump together if you call around. my tips for replacing the pump-
1. DO NOT PRY ON ANYTHING!
2. DO NOT PRY ON ANYTHING!
3. be sure you remove the TC lockup solenoid,
4. 2 pairs of vise grips are your friend to pull the pump
5. make sure you align the gasket correctly, a little grease helps hold it in place, and thread 2 bolts in, once you get the pump aligned. the bolts have o-rings.. make sure you dont over torque them, and tighten all of them or you'll have a leak..
6. There are 2 different types of pump, make sure you get the right one (o-rings on input shaft are different.)


it's not a difficult job, good luck! If i found a trans for sale for $300, i'd just replace the trans, but you never know what youre getting with a used 4l60e.. and it's nice to know how to fix things..