Guess I'm not sure what you mean. To change the WHOLE assembly, still assembled, as one unit (the diff/axle housing with all the guts still inside; differential, ring/pinion, bearings, snub axle shafts, etc), you're lookin about 2.5 hours. To change JUST the differential unit itself, I'm guesstimating 4-5 hours (at this point you've pulled the whole assembly and are now opening it up to change the differential). To completely over haul it (overhaul meaning you're starting out with a bare housing, so you're installing all the bearings and races, setting up pinion depth, and ring gear back lash, installing all the seals, snub axles etc), your looking at closer to 8-9 hours. When doing a complete overhaul like this, more often than not it makes sense to buy a complete assembly instead. By the time you add up cost for the individual parts and all the labor, the assembled unit is about the same price or cheaper.