It's possible you had sediment collect around the drain and restrict the flow. You should be able to drain the whole shebang using the draincock.
If you run into a problem, pulling hoses is usually the answer. She'll drain real nice (and real sloppy) with no bottom hose. You can similarly drain the overflow by pulling its hose off the radiator neck.
Going the yanking hoses route, you will want a very large bucket, and you may want something to protect the floor.
2006 WK Laredo 4x4 4.7L
1993 ZJ Laredo 4x4 4.0L — Dead, sold, and rolling again