SONICMASD
Adventurer
Regarding the rear diff - The axles popping out of the diff is a known issue that Mitsubishi fixed on models built October 2005 and later. There are new stub axles with a bigger groove and bigger circlip in them to fix this issue, or for cheap, you can just replace the circlips with the new bigger ones. Even though replacing the stub axle with circlip is the 100% correct way to go, many ppl have just replaced the circlips and I've not seen any repeat failures reported after this. Unless the rear diff was run without oil then I would expect it to be in good shape, they're pretty much the strongest rear diffs you can find stock on an SUV.