Series ROC motors are rated for Rock Crawlers. If using a Hotwire turn on sensor. if not set sensorless. using hotwire will open that function. LED's 5,6 & 7 should flash by turning the pinion by hand slowly. Hotwire does open other files than the blinky mode. Hotwire Shows Sensor or sensorless, motor timing and boost.

Not into rock Crawlers, would think smaller pinion would work, Try larger pinion. see if it improves.