I do appreciate you helping out with ideas Engifineer. I am somewhere in the middle breaking parts on my way to proficiency.

https://www.s2ki.com/forums/s2000-un...ating-1194139/ do you think this could be the issue?

 

I said research because it seemed like you're just spraying parts at it, and missing details well known.

You said axles appear to be oem, because they're similar to the other axles you bought, which were...aftermarket.

If I understood, there was a set of axles on the car, with clean cups (which we now understand means no pits?), and we can't be certain those axles were oem. Then a set of 'rebuilt' axles were purchased, and these seem similar to what was on the car.

How do we know all 4 axles aren't actually aftermarket?

 

I said they were OEM. From my second post. "I had the issue with two OEM(axles), one OEM one A1Cardone and Two A1Cardone." from my 4th post "As far as the first being a copy axle that may be true but they look identical to OEM axles" I would be shocked if they were not OEM. It is a low mileage car and there are thorough service records none mention an axle. The original axles also have OEM style clamps on the boots in addition to everything else I mentioned.

I was forced to replace a lot of parts because the passenger axle was fused in the hub. I tried to super cool and heat it with dry ice and torches. Used ATF, Acetone and Penetrant overnight under a 20 tonne press. Broke two tools made specifically for the task at hand. Slammed it with a sledge and airhammer for hours on end. At that point I needed to replace the spindle, hubs, and passenger axle.

How about the pinion bolt mentioned in that post, or bad mounts that have less obvious cracking. Or the driveshaft/axle bolts they look very worn out and have been hard to torque evenly and remove.