Hi Check out Phils site or Darkiths ,for instructions on how to reset the board you will need to put the jumper in to do this.As for the trim being over fully,check the tracks to make sure they are both free and not fouling,I think it will be something slowing one side .Check both tracks ,make sure they both have the same amount of slack and are running correctly ,sometimes the Panzer3 tracks jump the rear idler and run offset,also check all the wheels and return rollers are free.
I f all the above are fine take a look at the gearboxes then the motors.
regards pete