I recently took my 2002 F150 4wd FX4 in tot he shop to have the rear axle seals replaced after noticing them leaking. After putting the truck on a lift the shop noticed a significant amount of vertical play on both rear wheels. They are concerned about wear on the housing and/or axles based on the amount of play and are recommending swapping in an entire used rear axle assembly. Based on an assembly swap and service is cheaper than a complete rebuild. The shop is searching for a 3.55 LSD assembly to swap in but I wanted to see how likely it is that something other than the bearings and seals are worn on these trucks with similar symptoms?

Based on searching I think I am getting a newer assembly but I am hoping for better news.

 

Nope nope nope. You dont need to swap the whole rear if the wheel bearings are worn Even if the axle shafts are damaged there are offset bearings available so you dont have to replace the shafts. If there is metal contamination in the housing it can be cleaned for the most part with some brake cleaner and rags. Then the magnet should catch the rest of it. It sounds like you have a lazy shop. bearing example

 

They can NOT give you an answer without pulling the axle half shafts.. Bearing OD will keep from wearing the housing.. Bearing ID is the axle shaft. Like mentioned, you can move the bearing slilghtly with an offset bearing/ seal unit, or you can buy NEW HALF SHAFTS....... new shafts with new bearings and seals would be a much cheaper idea......... unless they can prove the pumpkin / gears / bearings in the center are bad.