I have a z-1 with a 310 reciever mounted in my pan car and whenever I turn the power on to the car the servo humms loud. It will steer but will not always return to center. I have my trim rates set to 0. I thought it might just be the servo so I got another one (futaba s3002). I just got this radio and before I used a jr 3xi radio with the same reciever and had no problems. Can anybody give me any suggestions on how to fix this problem. Thanks.

You may need to have the transmitter and receiver sent back to have it calibrated/ fixed. The steering pot is probally bad.