Why Does the Automatic Transmission Make a Thud When Shifting to Reverse?
1 Answers
Because the reverse gear lacks a synchronizer and the vehicle wasn't fully stopped when shifting. Here are the detailed explanations: 1. Electronic linkage between the brake system and automatic transmission: If the clutch isn't fully depressed during gear shifting, it can cause gear damage. Additionally, keeping your foot on the clutch when not in use leads to excessive wear of the release bearing. 2. Idle gear shifting: In automatic transmission vehicles, the engine RPM is very high during the first few seconds after startup. If you shift from neutral to reverse before the RPM stabilizes, it creates strong impact vibrations in the transmission, potentially damaging the gearshift switch. The correct approach is to wait until the RPM displayed on the dashboard stabilizes before using reverse. 3. Reverse gear lacks synchronizer: The synchronizer is an internal transmission component that ensures smooth gear engagement during shifts. Some vehicles don't have synchronizers for reverse gear, making shifting more difficult. Moreover, to distinguish it from forward gears, most vehicle transmissions don't include synchronizers for reverse gear. This explains why reverse gear is harder to engage and sometimes produces unusual noises. 4. Shifting before complete stop: When parking, you should first bring the vehicle to a complete stop before shifting from D to P. If you shift to P before stopping completely, the P lock hook inside the transmission will strike the gear with a thud. This operation can wear or even break the lock hook, and in severe cases, may render the transmission unusable.
