Why Most Semi-Trucks Don't Have Synchronized Transmissions

While automatic transmissions have their benefits, plenty of semi drivers prefer to shift gears themselves. Mastering the art of smoothly shifting a semi truck's manual transmission is no small feat, and can take years to perfect. Among truckers, being able to shift gears smoothly is considered a badge of honor and differentiates the most experienced drivers from those who are newer to the profession. Part of the reason that American semi truck manual transmissions are notoriously difficult to shift is that most are unsynchronized, meaning the driver has to manually match the revs between shifts.

In Europe, synchronized manual transmissions are much more common, and they help make the learning curve less daunting for newer drivers. Despite being the more accessible choice, synchronized transmissions haven't caught on in America. Given the rising popularity of automatic transmissions, they will likely never become as popular stateside as they are in Europe, either. That's partly down to American drivers' perceptions of synchronized transmissions, but it's also because there are other appealing options available.

Simpler, traditional unsynchronized transmissions tend to be cheap to buy, and there's also a perception that they're more reliable over the long run. That perception might not be accurate with the latest synchronized transmissions, but it still influences the buying habits of fleet managers. Even if you're an owner-operator responsible for the upkeep of your truck, there's a benefit to picking the tried-and-tested option — especially if you're already experienced with an unsynchronized transmission.

Truckers confident in their shifting abilities and who want a traditional, straightforward big rig will likely continue to stick with unsynchronized transmissions, since there simply isn't much reason to switch. Meanwhile, owner-operators looking for maximum driving ease will probably opt for an automatic transmission, which removes the need for drivers to shift gears themselves. Fleet managers also benefit from buying trucks with automatic transmissions, since they're much easier to drive. This means that companies can hire and train new drivers more easily: Once they have their CDL, they'll be ready to hit the road. That leaves little reason for truck buyers to opt for a synchronized manual transmission, which is why they remain a rare sight in America.