What Causes Body Shaking During Automatic Transmission Gear Shifts?
2 Answers
Body shaking during automatic transmission gear shifts occurs because the transmission gear oil is relatively viscous and dense, causing the drivetrain to more noticeably receive the power transmitted from the engine, resulting in a momentary body shake. Once the vehicle gets moving and the transmission gear oil warms up, becoming thinner and less dense, the situation improves. An automatic transmission eliminates the need for the driver to manually shift gears, as the vehicle automatically selects the appropriate gear based on driving speed and traffic conditions. Automatic transmission vehicles typically have six gear positions, arranged from top to bottom as: P, R, N, D, S, L. For general driving needs, using just the Park (P), Reverse (R), Neutral (N), and Drive (D) gears is entirely sufficient when operating an automatic transmission vehicle.
Last time I encountered the issue of body shaking during automatic transmission gear shifts, I found it was mainly due to these situations. Aging and hardening of engine mounts can lose their cushioning effect, causing engine vibrations to directly transfer to the body during each gear shift. Transmission fluid that hasn't been changed for too long becomes viscous or insufficient, leading to unstable oil pressure during gear shifts. Worn-out spark plugs with increased gaps can cause shaking during low-RPM gear shifts due to poor ignition. Carbon buildup clogging the throttle body and fuel injectors can result in uneven engine power output, causing jerky gear shifts. Insufficient fuel system pressure can lead to noticeable body trembling during sudden acceleration or upshifts when fuel supply can't keep up. I recommend starting with the simplest maintenance tasks, such as replacing spark plugs and cleaning the throttle body. If the shaking reduces, it saves a lot of hassle. You can check the engine mount condition yourself by opening the hood to see if the rubber mounts are cracked or leaking. These checks don't take much time but are very effective, at least for initially ruling out common issues.
