You might have a bad servo. Unplug the servos and try one at a time. Remember that there is two CH1 slots on Traxxas Receivers.
CH1 is steering servos
CH2 is throttle and brake servo. (Third slot up from bottom)
If nothing works are the Transmitter and Receiver bound together?
What color are the LED lights on the Transmitter? The color of LED light on receiver? They will be red or green. Solid or flashing.