What is the situation when the first gear of a manual transmission cannot be engaged?

[CarmenLynn]

Introduction to the reasons why the first gear of a manual transmission cannot be engaged: Insufficient lubrication of the transmission oil inside the gearbox: If the transmission oil inside the gearbox is not fully lubricated, starting the engine for a while before shifting can solve the problem. However, if the damage occurs in the internal transmission mechanism, such as gears, synchronizers, or shift forks, repairs are necessary. Incomplete clutch disengagement: You can try pressing the clutch pedal all the way down to see if the gear can be engaged. If the clutch components are damaged, repairs are required, including replacing the friction plate, pressure plate, and release bearing. Worn shift push rod: If the shift push rod is worn, making it difficult to engage the gear, you can try shifting multiple times to see if it works. If it still cannot be engaged, you may need to call for roadside assistance.