If I cannot work to pay for my auto loan for my work vehicle, is this valid grounds for filing bankruptcy?

Filing for bankruptcy is a significant financial decision.  Such action will negatively impact your credit rating and your ability to obtain credit in the future.  It will also remain on your credit record for a period of [7 to 10] years.  Thus, it is important to consider the long-term consequences such an action will have.

If you are unable to make payments on a debt secured by a piece of personal property (such as with a truck), the creditor (the entity owed the debt) will collect the item (commonly known as repossession) and sell it to cover the debt you owe.  If they are unable to sell it for the amount you owe, you are expected to pay the difference.  For example, assume you paid $10,000 for the truck through a loan you received from a bank.  You have not paid anything toward this $10,000 debt and the bank repossesses the truck.  Then assume the bank sells the truck fro $8,000.  You will still owe the bank $2,000.  However, if the truck sells for the full amount owed (here, $10,000), then you will not owe the bank any additional money.

If you are unable to pay your debts, you may be able to file either Chapter 7 or Chapter 13 bankruptcy, which will eliminate your debts or at least structure them into a reasonable payment plan.  A bankruptcy attorney would be able to advise if a bankruptcy court would approve your situation and can offer advice one what the best decision might be for you financially.