In tearing down my gearbox, I’ve found the driven gear (C.21310) is almost knife-edged. Given that replacements are 200 smackers it’ll go back in til it fails, perhaps with another owner. The driving gear is a bit better, but not by much. Costing another wallet-full of Jacksons, back in it goes. With proper lubrication they’ll be OK.
Any wonder a properly restored E costs $200K?
I withdrew it and found that the reason it’s so worn out is due to the sludge-like consistency of the oil on it’s shaft. So, when you have the ability to do so, take yours out and flush out the sludge. This looks like it’s possible while in the car. The gear you rescue will thank you.