Should I do a voluntary repossession or fix the car?

Should I do a voluntary repossession or fix the car? - 1
Added (1). I have a 2002 ford ranger that I financed less than a year ago. The engine is dead and the truck has 170,000 miles on it, I still owe credit acceptance 8,000. Should I do a voluntary repossession? Should I try to work out a settlement and buy a new car? Or buy a used engine and keep making payments? The car is worth 4,000 in great condition from blue book.
Added (2). The dealership has offered to fix it for 6,000. That doesn't include the teardown which is already 1,500. I don't know if that is brand new or what, I haven't looked for deals.

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