The Dana 35 rear axle in my parents' 1993 Grand Cherokee is getting noisy, so I tore into it expecting to find bad bearings. Sure enough, I did.
I've rebuild axles before, but this is my first c-clip axle. As I pulled the shaft out, I expected the wheel bearing to be pressed-on to the axle shaft, but to my surprise the bearing rides on the shaft itself. The shaft is the inner race for the roller bearing. The axle shaft bearing surface had some pretty nasty spalling on it, which now means both shafts will need to be replaced.
If this was a traditional bearing-retained axle, the bad bearings could simply be pressed off and new bearings pressed on, but because of the c-clip design where the axle shaft is the bearing surface, the whole shafts need to be replaced.
What kind of stupid design is that!? A stupid one is he answer.
Not to mention the axial load on the wheel while cornering is routed through the full length of the axle shaft and into the differential side gears and center pin, through the carrier, and through the carrier bearings to the differential case, causing extra stress on all of them and likely shifting the relationship of the gears. A bearing-retained axle isolates the major length of the axle shafts and the entire differential assembly from axial cornering loads.
Stupid design. it made it 250,000 miles, so I can't curse it too bad, but it's stupid from an engineering and repair standpoint. $60 to replace wheel bearings on a bearing-retained axle verses $400 on a c-clip axle.