Autozone usually keep all of your infor in the symstem when u purchase things that are under lifetime warranty...they can usually pull it up by your phone number if u dont have the receipt...if u do not take them the old part u'll have to purchase a new pump which u will be refunded once u return the old pump...thats how its always worked for me when i've needed to change brakes and alternator...and even my fuel pump..buy new part...change...and return old parts for my refund.
