Bachman Dual Mode Two Truck Climax with sound

[GNmodeler1988]

My Climax has a dual mode decoder. I am using an MRC Tech 6 cpowerpack with throttle. Every time I plug in the powerpack I have to select my Locomotive # which is 3. I got Loco, followed by 3 then enter. When I do that my Locomotive starts out at 126 (top speed) instead of starting out at 0 like it used to. I did something. Does anybody know how to fix this?