RepairPal, a US-based creator of an estimator platform for car maintenance, secured $5m from car retailer CarMax on Wednesday as part of an expanded commercial partnership. The cash forms part of a new funding round for RepairPal, though further details have not yet emerged. RepairPal previously obtained an undisclosed amount from financial services provider USAA in 2014, adding to a $13m series B round in 2013 backed by lubricants producer Castrol and auto marketplace Cars.com. Existing backers also…