What Causes the Abnormal Noise When Shifting to Reverse Gear in an Automatic Transmission?
2 Answers
It is caused by excessive or insufficient gear clearance. The details are as follows: 1. Gear backlash refers to the distance along the normal direction between the non-working surfaces of a pair of meshing gears. A pair of installed meshing gears must have a certain amount of backlash to compensate for manufacturing and installation tolerances, elastic deformation under load, and thermal deformation. It also helps store a certain amount of lubricating oil to improve the lubrication condition of the gear surfaces. 2. Generally, the smaller the gear clearance, the better, as long as it ensures normal operation. During manufacturing, the clearance is set according to the required precision level of the gears.
I've been driving for almost twenty years, and encountering abnormal noises when shifting into reverse is a common issue. It's mostly due to misaligned gears inside the transmission or worn clutch plates, especially in winter when the fluid isn't warm enough, which can exacerbate the problem. It could also be caused by looseness or dirt buildup at the shift lever mechanism connection, leading to friction sounds during gear engagement. Checking the transmission fluid is crucial—if the level is low or the color is dark, it should be replaced promptly to maintain lubrication and reduce noise. For safe driving, avoid shifting into reverse abruptly before the car comes to a complete stop; develop the habit of stopping first before operating. Regular maintenance, including transmission inspections, can prevent minor issues from turning into major disasters—a single oversight could damage the entire drivetrain. Don’t ignore these details; addressing them early ensures a more worry-free driving experience.
