01 Rodeos did not have auto locking hubs. They had drive plates that connected the wheels to the axles permanently. The PO did you a favor by converting to manual locking hubs. But, this is just for informational purposes and is not relevant to your problem.
I'm not quite clear on what part you are talking about that is longer than stock. I think the terminology you're using could be the problem. Maybe you could snap some pics?
Also, you might want to try
here. That forum is much more active and has a lot of Isuzu lovers that have all sorts of knowledge.