Another simple thing you can do is see if your brakes are locked on for some reason. Have you tried rolling the car with everything off? Have you adjusted the brakes in any way? Get the manual out and check your linkage to see if it's stuck or something. One other thing to check is the failsafe. If the receiver is experiencing radio interference or the batteries are weak onboard, then the failsafe puts the brakes on by default. The above items are easier to check than pulling apart the entire truck. Hope this helps, Steve.