What Causes Fifth Gear to Pop Out?
2 Answers
Fifth gear popping out can be attributed to the following reasons: Self-locking mechanism failure: To prevent gear disengagement during driving, transmissions are typically equipped with a self-locking device. If this mechanism becomes damaged (e.g., broken self-locking spring, fractured self-locking ball head), it can easily cause gear disengagement. Severe synchronizer wear: When components like the synchronizer sleeve lock ring or sliding blocks experience significant wear, the synchronizer may overcome the locking force of the self-locking device during high-speed rotation, causing it to slide out of the engagement gear ring and resulting in gear disengagement. Severe wear of shift lever or fork: If the shift lever or fork becomes severely worn, the fork may fail to properly position the synchronizer into engagement. This prevents perfect meshing between the synchronizer and engagement sleeve. During high-speed rotation, the synchronizer can then slide out of the engagement sleeve, leading to gear disengagement.
I used to frequently experience fifth gear popping out when driving manual transmission cars, which was really frustrating. The most common cause is wear on the gears or synchronizers inside the transmission. Over time, the teeth don't mesh securely, especially during acceleration when it's prone to popping out. It could also be due to loose or aged shift cables, causing the shift lever position to be inaccurate and preventing full gear engagement. If the clutch pedal height is improperly adjusted and the clutch isn't fully disengaged when released, it can also lead to incomplete gear meshing and automatic disengagement. Additionally, excessive vehicle vibration or aggressive driving can cause shift fork displacement, exacerbating the issue. When encountering this situation, I recommend immediately checking if the transmission fluid is clean and at the proper level. Dirty fluid increases gear friction and raises the risk of gear popping out. Getting it repaired once can solve many problems—don't delay until major damage occurs.
