We hope that you enjoy your remanufactured engine, transmission, or differential. Upon receiving your remanufactured part, we need you to do a couple things so that we are able to keep our prices low and can continue to serve other motorsport enthusiasts! There will be a prepaid return shipping label in the package you receive. All you have to do is take out your new product, place your core back in the packaging, tape the label to the package and drop off at either a UPS or FedEx. It is important that you ship us your core back within five (5) business days of receiving your remanufactured part. If you do not do this, we will charge your credit card a core charge! We believe honesty is the best policy, so we trust that you will send us your core back, so that we do not have to impose a core charge on our products. If for some reason you do not receive a return shipping label please let us know as soon as possible, so that we can get you one! If you have any further questions, please do not hesitate to reach out to us