So I had a crazy experience. I was running my T740 along the hillside and knew it was getting lower on fuel, but it suddenly shut off and then I rolled backwards down the hill. It appears that the brakes would not hold without the engine running. Luckily it rolled a short distance and it flattened out, and I never hit anything. From what I can tell the brakes work fine when it's running, but don't hold if it is not running. Any ideas on what could cause this?