Our Semi trucks and Highlifts use 3speed transmissions for more maneuverability and true scale realism. Whether you're hauling a big load or climbing some rough terrain, the ability to shift into low gear can make the difference. High speed runs are no problem once you kick it into 3rd gear, when its time to move out! Both vehicle types require a 4 channel stick type radio for full function. If you're going to outfit your vehicle with one of our multifunction units (MFU), you will need to choose a analog radio. Shifting into gear is extremely easy once your transmission is adjusted correctly. Below you will see the basic concept on how the servo moves the transmission into all three gears. It is best to get the transmission adjusted with your trims centered and only using the collar on the transmission rod to adjust final increments. This will allow for the best operation if you're using a MFU unit.