The Vehicle Payoff Sample Letter form is a crucial document for individuals aiming to transfer their vehicle loan to the State Department Federal Credit Union. Use the Auto Loan Calculator from Suffolk Credit Union to figure out your monthly payment so you know what to spend on a vehicle.A payoff letter provides instructions on how to pay off a loan with a lump sum before the loan term ends. Learn how payoff letters work. Warrant payoff letter. Tax credits and deductions, filing status and residency status can influence what you pay. Student loan payoff calculator.