I was having the same issue that several other people in here have had. The 4x4 shifter in the floor was very difficult to engage. As a matter of fact, I couldn't get mine into 4LO at all. Well, the more I thought about it and the more I read up on it, I just had this feeling it was something simple. So, without someone up in the cab to move the shifter, I tied a long piece of twine to the shifter arm and climbed under the truck to look at the linkage as I pulled. I wanted to see what was supposed to be moving underneath when the shifter was being pulled to the left. That's when I saw the problem. The first thing you see is the very bottom of the shifter, which looks more or less like a 2-prong fork. That is what helps move the linkage from front to back. Right above that about 2 inches is a bolt that keeps the shifter rod against part of the linkage that should twist from left to right, such as when you pull the shifter towards you to begin pulling it back into Neutral and then 4LO. The head of that bolt above the fork has snapped off. So, I can shift into 4HI ok, but I can't shift it into 4 LO until I find out how to fix the broken bolt. I was able to slip a long flathead screwdriver into the linkage and twist it from left to right, so I know it's not bound up. There are two problems that I see for fixing this. The first and obivous one is that it's in a really tight and awkward spot, so getting to it will be difficult. The second is that the inside nut that is still attached looks like it may be welded in there so if that's the case that is going to be difficult to fix.

I hope some of this makes sense. If anyone has had this happen, please let me know what you did to fix it, or if you have any suggestion I would appreciate it. Thanks.