Whatever kind of ATF you have around the house. If you don't have any, buy the kind your transmission uses.
Alternatively, you could use a little bit of lithium grease - pop the ball and socket link, and dab a little on there.

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It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D