I apologize for having to respond to your comments in this way, but after putting 525,000 miles on my 240D with absolutely NO transmission problems, and only two clutches, and 175,000 or so miles on my 300E five speed, and many other miles on earlier Benz manual transmissions, I have to question your ability to drive a manual transmission properly.
Sorry, but that's how I see it.
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in