Why Does the Car Body Shake When Shifting from D to R?

[DiIsaac]

Engine idle speed issue. Solutions: 1. When starting a cold engine: Allow the car to idle for one and a half minutes to give it a warm-up period. At the initial start, the internal temperature of the engine does not reach the normal operating temperature—the normal temperature is indicated when the water temperature gauge reaches 90 degrees. The car may shake, the engine noise may be loud, and the tachometer may be slightly higher—normal values range from 600 to 900 RPM. Starting under such conditions can easily lead to carbon buildup in the engine because combustion is incomplete at low temperatures. 2. Avoid lugging the engine while driving: When the engine starts to shake, downshift promptly. Lugging the engine can cause excessive pressure, insufficient power, incomplete combustion of gasoline, and carbon buildup in the injectors, affecting the engine's lifespan. 3. Protect the undercarriage: The undercarriage is the part of the car closest to the ground and is highly susceptible to damage from road objects. Therefore, regularly inspect the undercarriage to prevent excessive damage from foreign objects.

[StJasper]

Last time I drove my friend's car, I also experienced body shaking when shifting from D to R gear. The mechanic later said the most common cause is aging engine mounts. Those are the rubber cushion pads under the engine - they become hard and cracked over time. When shifting gears, engine vibration gets directly transmitted to the frame, feeling like an earthquake. Also, loose transmission mounts can cause similar symptoms. Generally, these rubber components last only 5-6 years. To check, have someone observe the engine's swing amplitude when you start the car and shift gears - if it exceeds 1cm, it's most likely a mount issue. If you don't replace these aging rubber parts, they'll eventually damage the engine and transmission mounting points, leading to much more expensive repairs.

[VanIsaac]

When experiencing body vibration when shifting from D to R gear, first confirm three points: How long has it been since the transmission fluid was changed? Dirty fluid can cause valve body sticking, leading to impact sensations during gear shifts. Have the half-shaft CV joints been inspected? Worn universal joints can result in uneven power transmission, especially causing resonance when reversing. Another possibility is severe throttle carbon buildup, which affects idle stability and subsequently gear shift smoothness. During my last maintenance, the technician used an endoscope to check the throttle, and the carbon buildup was almost blocking half of it. After cleaning, the gear shift vibration significantly improved. Regular fuel system maintenance can actually prevent many vibration issues.

[FrankMarie]

Here's a real experience from a German car owner: When I shifted from D to R gear, my car shook violently with a loud clunk. At the dealership, they connected the computer and found the fault code indicated a transmission adaptive learning value disorder. The technician explained that the ECU had memorized incorrect shifting parameters. After recalibrating the clutch semi-engagement point, it worked normally. For older vehicles, abnormal wear of the torque converter lock-up disc should also be considered, which is quite troublesome to repair. It's recommended to perform a transmission reset learning first. The specific operation involves following a particular shifting procedure when the engine is cold to let the ECU relearn.