We tore down the differential and all looked pretty good inside. We visually confirmed that we had 4.10 gearing as expected. One area of weakness we should note is that of the factory differential carrier which has been known to crack when used fairly hard. A second weakness of this axle assembly is where the axletubes enter the differential housing. Ford secured each tube to the housing with three steel rivets that pin the tubes in place. Under harder use, it's possible to spin these tubes in the housing. The common solution is to run a circumferential weld at this joint.