What is the function of a synchronizer?

• A. align the driveshaft with the differential
• B. align speeds to prevent gear clash
• C. ensure that components rotate at the same speed
• D. none of the above

Answer: (B)

A synchronizer’s job is to match the rotational speeds of the gear and the shaft so they can mesh smoothly. When you shift, gears are turning at different speeds, and engaging them directly would cause grinding. The synchronizer uses friction surfaces to bring the gear up (or down) to the same speed as the shaft, then a locking mechanism (dog clutch) holds the gear in place. This speed matching is what prevents gear clash and allows a clean shift.

That’s why the correct choice is that the synchronizer aligns speeds to prevent gear clash. It isn’t about lining up the driveshaft with the differential, nor does it continually keep all components rotating at the same speed—its purpose is to equalize speeds temporarily during gear engagement.