Why is there sometimes abnormal noise when shifting from first to second gear?
2 Answers
Here are the specific reasons for abnormal noise when shifting from first to second gear in a car: 1. Casing damage: The transmission casing and bearing seat holes have long-term wear and deformation. The noise is loudest when engaging low gears, gradually decreases when shifting to higher gears, and is minimal in direct drive. 2. Due to individual gear surface breakage, causing impact during meshing. When engaging this gear, strong impact and vibration occur, leading to resonance in the transmission casing. 3. Improper transmission assembly: Incorrect replacement of gears, needle bearings, or bushings in a certain gear of the transmission, or abnormal assembly clearance, resulting in poor gear meshing and abnormal noise during transmission in that gear.
From years of driving experience, it's quite common for manual transmission cars to make unusual noises when shifting from first to second gear, especially in older vehicles. The most common cause is worn synchronizers in the transmission, which are responsible for matching gear speeds and can produce clunking or grinding sounds when worn. It could also be due to insufficient or degraded transmission fluid, leading to inadequate lubrication and increased gear friction. Improper operation, such as not fully depressing the clutch or shifting too quickly, can also cause impact noises. It's advisable to first check the transmission fluid level and quality, replacing it if necessary. If the noises occur frequently, promptly visit a repair shop for diagnosis—don't ignore them, as they could develop into more serious transmission failures with higher repair costs. Preventive measures include regular maintenance and fluid changes, and ensuring the clutch is fully depressed before shifting.
