Is the "Voluntary Disability" CASDI and/or CAVPDI? I'm assuming so, as every worker in CA is required to pay one or the other, and you didn't list it separately.

In either case, it should only be 1.2% of your income, and should not exceed $1,601.20 for the year. Ask your employer why they're deducting so much. It's a flat rate so it shouldn't be affected by your W-4.

If it actually refers to a private disability plan and not the state disability tax, then you're paying a lot for disability insurance and should also ask why.