I posted this somewhere else, but here it is. Get the top fitting threaded first. You need to have it on an angle and having the bottom threaded first doesn't help. Just be sure watch where you snake the other end so the fan fitting will go in.
Moparonlineparts has good prices, but charges a handling fee. Go to the vendor site here and contact Avondale parts. He's very competitive with his prices and I have ordered several times from them with good/quick service.
2004 GC Spec. Edit. V8 4x4 Quadra-Trac II. Bright Silver Metallic Clear Coat, 4" lift, RE shocks, adj. JKS CAs all around, 265/75/16, ProtoFab winch bumper, Vortex 10,000 lb. winch, dual OME steering stabilizer, Rockyroad rockrails, skids, JKS Discos. Addco front & rear sway bar, & Aussie locker.