Core charges are charged IN ADDITION TO THE PRODUCT PRICE, and are refundable when USABLE core product is returned to ATS Diesel Performance. Core credit returns will be accepted within 90 days of original purchase. After 90 days Core credit refunds will be at the discretion of ATS Diesel Performance. Sutherland Diesel Performance uses a carrier that provides package tracking to ensure your product gets back to us safely and quickly. You will not be reimbursed for shipping costs incurred in shipping the core. Cores that have been disassembled or have missing and/or damaged major components will not receive full core credit. All core charges are refunded by check, mailed to the billing address on file.