How And When Can You Refinance A Auto?

Is it a good practice to refinance a car or truck. I recently purchased a home and the payment is somewhat large. I was in need of transportation before I purchased the home. I was thinking It would hinder the mortgage process if I bought a new vehicle before the house. I want to know is it worth refinancing the auto to make my money and budget work out. I did not buy this auto just to be buying, I bought it because of need and the condition of my 92 van is horrible. There is no heat and many