How do I list a vehicle if it is total loss due to 500,000-miles and blown engine and tranny. how would I file as the total loss?

Is this a car that was used for self-employment?   If it was your personal vehicle there is nothing to enter about that on your tax return.

If this was for self-employment, you would mark it as stopped using.  It wouldn't be considered a loss.  If you sold it or scrapped it, you would mark it as a sale.

If it was for personal use, or going to work, you would not note it on your taxes.   

 

If this is a business vehicle, it should be listed as an asset on your business.  You report that you stopped using it.  Or, if you sold it for scrap, report that you sold it for the price you received for the scrap metal.  If there was depreciation remaining, you will get the rest of that on your return (although that seems unlikely at that age).  If you sold it as scrap and got more back than the current depreciated cost basis, you might even have a small amount of business income.