Can I get trade in value for a second car on another car that I have already purchased?

You can not change the loan, or add a trade in to the deal at this late date. You can sell your car, either to a dealer or a private party.

The first step is to call your lender (the one who you own money to on the Camaro) and get a payoff amount on your loan. When you sell the car, that amount will have to be paid off out of the proceeds of the sale. Any excess will be yours to do what you want with. You can apply it to the VW loan, you can use it for other expenses or you can put it all on "red" on the roulette table in Vegas. It is your money!!

A dealer is only going to give you wholesale price for your car. If you want to get top dollar for it, have it professionally detailed, have any needed state inspections done, and make sure things like the oil change is up to date!

Advertise the car, either in the local paper or in a place like craigslist or Autotrader.com. If the car is desirable, and priced correctly, it should sell.

Depending on the dealer and who made the loan to you, yes. Any money over the loan payoff could be applied towards the principal on your loan in most cases. Call the dealer and ask.

Good luck.