What can cause a transmission to be hard to shift?

A transmission can become hard to shift due to several factors, and one significant contributor is worn blocker rings. In a manual transmission, blocker rings are essential for synchronizing gear engagement. When they wear down, they fail to effectively synchronize the speed of the gears during shifting, making it difficult to smoothly change from one gear to another.

Additionally, if the linkage is out of adjustment, this can also impede the proper movement of the transmission gears. The linkage connects the gear shifter to the transmission and is responsible for positioning the transmission in the correct gear. If it is improperly adjusted, the shifter may not align correctly with the transmission's selector mechanism, resulting in hard shifting or difficulty in engaging certain gears.

Both worn blocker rings and linkage issues can independently lead to a hard-to-shift transmission. Therefore, the answer encompassing both factors accurately reflects the complex nature of shifting problems in manual transmissions. Each component plays a vital role in ensuring smooth gear changes, and failures in either can significantly impact the driver's ability to shift gears easily.