Identifying Auto Service

Your transmission has one critical job: transmit power from your engine to your drive wheels. While performing this duty, it may also transmit undesirable vibrations from the transmission housing to the vehicle chassis. These vibrations can produce harshness in the cabin, leading to an uncomfortable ride and noticeable issues when shifting.

Since a rigid connection to the chassis would create a significant amount of noise and vibration, your transmission instead uses rubber or fluid-filled mounts for isolation. Due to the amount of stress placed on these mounts, they may wear out over time. Worn mounts can, in turn, produce several troubling driveability issues.

Early Signs of Trouble

Depending on the underlying cause of failure, transmission mounts may fail gradually or suddenly. Gradual failure is typically the result of rubber components wearing out, breaking down, or plasticizing over time. Less pliable rubber cannot provide effective isolation, reducing the efficiency of the mounts. Fluid-filled mounts may break suddenly, losing most or all of their ability to isolate the transmission.

If your mounts are in the early stages of failure, then you will most likely notice an increase in cabin vibrations. In some cases, you may notice vibration near your gear lever or towards the center of the car, but it can often be challenging to pin down an exact location. Pay special attention to vibrations that seem to vanish when your vehicle is in neutral or park.

Progressive Problems

As the situation worsens, you will likely notice more severe symptoms. If your mounts are especially worn, you may hear loud clunking noises as the transmission physically shifts under the car. Thunks or clunks will typically be most audible when under hard acceleration or braking as the transmission moves towards the back or front of the vehicle.

With manual transmission cars, another potential symptom is difficulty moving the shifter into gear. You may notice this more in turns, as the weak mounts allow the transmission to move and disrupt the linkage between the shifter and the gears. The more worn your mounts are, the more severe the problem will become.

Ongoing Damage

Transmission mount failure is more than just an inconvenience. In addition to reducing cabin harshness, isolating your transmission also helps to keep critical components aligned. Severe wear on mounts can place additional strain on drivetrain joints or CV joints, depending on your car's drive wheel configuration. Leaving the problem for too long can damage or destroy these components.

If you notice harshness issues that may be the result of failing transmission mounts, always have your car evaluated by a professional transmission shop as soon as possible. Transmission mount repairs are relatively low-cost, especially when compared to the damage that they can cause.