I dont think this is a E8000 gear?The end of the axle is chamfered, I think you mean there is a shoulder on the axle to stop the bearing being pushed on too far, and yes, in most cases you would be right. I am just trying to guess what is causing your gears to rub? I am guessing you did remember the spacer shim that's shown in the photo below?
View attachment 74981
The black gear on my E8000 axle doesnt have a bearing, its just fixed in place (i assume pressed). And i never took it off anyway. Just removed the bearings on the end, and replaced with new bearings. There is no shim on that axle.
Imo the probable cause is still the huge amount of wobble and free play of the clutch gear. Because it is so loose it allows the gear to pivot on the axle. Enough to get it to collide with the other gear. Add in the sideways force from the helical tooth pattern and there is a recipe for disaster.
Sadly i cant measure the pivot range now (got the motor back on the bike) but from what i estimate its about 2-3mm at the teeth of the gear. That is a lot of free play if you ask me. Especially for a gear that only has about 1 or 2mm's before it collides with the other gear. Near the E-clip there is about ~0.4mm of clearance (also estimate, didnt have a feeler gauge with me), but that tiny amount of clearance translates to that that 2-3mm of pivoting range near the teeth of the gear. Too much if you ask me...
Oh and yes, i meant the word "shoulder" instead of chamfer. The shoulder is what i pressed the bearings up to. I would assume this is how its supposed to be done, right?
Ive posted the exact bearing puller i used with a link to buy it a couple of pages back. Im not gonna claim its ideal for the job though...