Ah, no. The TDI alternator has an overrunning clutch pulley.
The problem with your alternator may well be the over running pulley which is replaceable for a lot less than the garbage alternators that AutoZone sells. The other problem that is common is a worn out brush/regulator assembly, also replaceable.
What are your symptoms? if you need to troubleshoot the overrunning clutch pulley, we can advise you.