I've bought a few vehicles new and rarely kept oil change receipts as most were done by me. Have yet to have engine/trans issues. I have had multiple issues with other components that were taken care of under warranty on a Ram I owned. Ball joints, radiator, rack and pinion, ring and pinion(frt and rear)...the list goes on. None of those repairs required proof of maintenance.....they did, however, force me to buy a different brand truck that has been much less "needy" on the repair front.