Could be a bent regulator, or a broken slide (attaches to regulator and slides in a C channel), or stripped gears on either regulator or motor.

The slide isn't hard to replace, just time consuming - patience)
The regulator is expensive new - if you don't want new, junk yard is an option.
Same for the motor.
Both regulator and motor can be found on ebay - count the teeth on the motor and verify brand/manufacturer.

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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