2002 Liberty rear end replacement

Hello guys. I saw other posts on here for repair questions, but if there's a better spot on the forums to ask then please let me know. The rear end on my Jeep Liberty is bad (ran out of grease very suddenly, and I didn't notice) and my mechanic is quoting me 1300-1500 to replace it with a used one. Looking around that sounds like a reasonable quote, albeit one I can't afford for a non-essential vehicle. I found a used rear end assembly here for under $500:

http://www.automotix.net/usedautopa...477247o.html?gclid=CM7ssqC62NECFd61wAodiyMAVQ

(I have one of the rare 3.7 liter, two wheel drive models and the mechanic said it was a dana rear end)

..and I didn't know if anybody here knew how difficult it would be to replace the rear end myself. I'd found a few people saying that on a Wrangler it's not all that hard, but I wasn't sure about my model. I'm decently mechanical, but I don't have lifts or anything and would have to buy a better jack, but if I can do it myself for the cost of parts and maybe another 200 in equipment then I can justify it to the wife to hold onto the vehicle which I've really enjoyed so far. Other than needing new tires the car is in good shape with 150k miles and a solid transmission and engine which is part of why I'd like to keep it around if I can (it also has my only towing hitch, which has come in handy and critical times). If it's a repair that can be done without having to get into much electrical or pneumatic is mostly bolts and getting dirty then I don't think it'd be much of a gamble to take care of myself.