IF I read propperly, you had the pump off the engine, then re-installed, and now it works off and on and squeels like a pig.
Jack the truck up and secure with jack stands.
Slowly turn the wheels back and forth from lock to lock a couple dozen times.
Walk away and play on the board.
Go back and repeat the turning from lock to lock.
Drop truck to ground and fire it up. Turn the wheel just a little bit, then kill it and check the fluid.
Drive around the block.
If all else fails, cut the belt that runs the power steering.
