06 or 07 jetta tdi

on cam shaft would any one know in the casting behind the casting that hold the timing belt , if removes is it spline or have some way so it doesn't lose it aliment, when reinstalled. thanks Jim

If the real question that you are asking is how to ensure that the camshaft and the crankshaft are in correct alignment during assembly, the answer is that you need to read the factory service manual and have the correct locking tools on hand, and use them correctly.

I have no idea what you mean by "the casting behind the casting that hold the timing belt".

Maybe he is asking if the camshaft pulley is spined to the cam?

If that is your question on a BRM which would be on a 06 tdi jetta the cam pulley is two parts. First part is adjustable with three bolts. 2nd part that actually connects to the cam, which I would call the cam pulley "hub" is indexed with something like a "keyway" built into the pulley and it will only go on the camshaft one way.