The aftermarket seal is not out of spec with respect to diameter.
The OEM seal came with flyer in the baggy saying "this new seal replaces the original seal to prevent leaks. this new seal locates the seal 2mm further up the axle".
I tossed the flyer or I would post a pic. Clearly, there are two types of seals that will work for this application.
Also, I checked the axial length/diameter relationship with the seal. The filleted shoulder of the axle is FLUSH against the bushing - it can't be pushed in any further. So, the only reason that the new axle COULD differ from the OEM axle is the transition from smaller diameter to larger diameter. Ironically, the filleted design of the A/M axle is SUPERIOR. Moreover, I PRESUME the OEM axle didn't ALSO have this design.
Hindsight being 20/20, I would have mic'ed the OEM axle and confirmed if the shoulder is filleted like the new axle.
It's a 50-50 shot that the OEM axle would have ALSO leaked. Since I returned it for a core, I don't know what type of shoulder it has.
