Taken from the DX2E manual available on the spektrumrc website.

The travel function supports precise endpoint adjustments in each direction for the steering and throttle channels.

1. Hold the trigger in the full brake position and the steering wheel in full right position while powering on the transmitter. The LED flashes rapidly, indicating the programming mode is active.

2. Throttle End Point: Hold the trigger in the full throttle position. Turn the TH TRIM knob to adjust the full throttle end point.

3. Brake End Point: Hold the trigger in the full brake position. Turn the TH TRIM knob to adjust the full brake end point. Return the trigger to the center position.

4. Left Steering End Point: Hold the steering wheel in the full left position. Turn the ST TRIM knob to adjust the left end point.

5. Right Steering End Point: Hold the steering wheel in the full right position. Turn the ST TRIM knob to adjust the right end point. Return the steering wheel to the center position.

6. Power off the transmitter to save the travel adjust settings. The minimum Travel is 75%, and the Maximum travel is 150%. The default travel settings are 125% steering and 100% throttle.

IMPORTANT: If the travel is changed on the DX2E, you must rebind and calibrate AVC® Receivers.