None of my service manuals have any information on the transmission, so I'm at a loss to decide how much effort I should put into it while it's out while I rebuild the engine.

How do I tell when to replace the clutch disc? It's quite convenient to replace while the tranny is removed from the engine, but it's also kinda expensive and I don't want to spend money unnecessarily. Can I measure thickness with a micromenter to decide whether it needs replacing? Will a visual inspection be adequate?

- Nathan
'83 240D, 255k miles
'00 New Beetle TDI, 25k miles