1997 Other Suzuki Models front drive bangs when in 4wheel dr

When I shift into 4wheel drive the front will make a banging noise after going for a ways. The harder the hill, the more often the bang. It will bang every now and then when I'm going down hill. It got to were it would even knock it out of 4wheel. I replaced an automatic locking hub with a used one. Its still makes a banging noise but not as bad. Thinking about putting in manual locking hubs. Seems Warn makes them for my model. Any ideas, if I put manual hubs on do I need other parts.