Some people do have a hard time for some reasonTom, how hard are the 4.10 gears to find nowadays if one wanted to do the re-gear? I feel like I remember some recent posts of people having a hard time locating them out of the 2.4 equipped Libertys.
I am running 4.10s on both the 04 and 03, all four diffs I have under 550 bucks in ( less the lockers)
I also have two sets of extra 4.10s diffs that I have less than 650 in them ( all 4 , front and rear )
Just picked up the last set a couple of weeks or so ago . People know I am always looking and I pay a finders fee for anyone that finds me some, so that helps
I check car-parts.com on a regular basis plus other local yards as well
One set I found in a scrap yard 5 minutes from where I was living at the time, just happened to see their truck hauling a KJ so followed it to see, yep a gasser 4 cylinder
So I guess in the end it's just looking, having a bit of luck and treating people right so they will find them for ya