Symptoms of Bad Transmission Mounts | Autance

Every smooth running engine needs supportive components that keep it securely attached to the frame of a car. These components…

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Symptoms of Bad Transmission Mounts | Autance © Symptoms of Bad Transmission Mounts | Autance

Every smooth running engine needs supportive components that keep it securely attached to the frame of a car. These components are none other than motor and transmission mounts. These mounts become defective with time and mileage , impacting driving comfort and resulting in unwanted noises as well.

What is a Transmission Mount?

Transmission mounts may be small, but the  impact they have on vehicle performance is undeniable. Mounts are responsible for a number of things including supporting the weight of the transmission and isolating vibrations from the passenger cabin. Both the engine and transmission mounts are similar in design and are made with rubber or filled with fluid in order to reduce friction between engine and car frame. Fluid filled mounts also double as shock absorbers that help keep vibrations to a minimum. Most transmission mounts have a longer shelf life  than engine mounts but leaks in the transmission system and climatic effects such as road salt and moisture can damage them in the long run.

Continuous pressure on the engine and transmission mounts eventually causes the rubber to deteriorate. When this happens, the engine may rise from its place during acceleration and fall back down with a loud thud once the throttle is released. Transmission mounts are also at risk of collapsing without showing any signs of external damage. When this happens, the mount itself becomes shorter in height, leading to engine vibrations that are hard to miss, especially when drivers place the transmission in reverse.

Symptoms of Bad Transmission Mounts

  • Thumping Noises

Signs of bad transmission mounts also make an appearance during driving. One of these telltale signs can be heard when the driver is forced to slam the brakes, resulting in a loud bang that is hard to miss. The same noise can be heard during acceleration as well, and may resemble the sound of a heavy mass colliding with the chassis or undercarriage of a moving car.

  • Shaking and Lurching

If your car greets you with an unsettling sound of repetitive rocking early in the morning the second you turn the key in the ignition, then this may indicate that your transmission mount is damaged. Bad transmission mounts are usually detected when front-wheel drive vehicles start rocking back and forth during start-up. This motion occurs from side to side in rear-drive cars such as trucks and SUVs and transforms into a steady vibration once the engine starts. Cars with a bad transmission mount will also lurch unexpectedly when the driver turns the ignition off.

  • Rigid Chassis

When the stable foundation of an engine or transmission becomes defective, other car parts begin to suffer as well. Therefore, when transmission mounts collapse or wear out, they adversely affect engine stability, resulting in a flexing  vehicle frame that eventually  makes the car difficult to drive.  Door hinges and weather seals are also affected and will begin to make creaking noises over time. A severely flexing vehicle frame will eventually lead to permanently damaged sheet metal and door panels that are out of alignment.

  • Bouncing  Engine

Most transmission mounts are engineered to allow a hint of movement in order to reduce noise, vibration as well as harshness. Faulty mounts can result in an unstable engine and excessive movements that can cause flexible components to become damaged. Drivers can put this symptom to the test by placing the car in drive with a tennis ball stationed above the air filter. If the ball rolls off the cleaner while the engine is running, then there is a big chance that one of the mounts is damaged and needs to be replaced.

  • Damage to Other Components

Unstable engines that move excessively can cause a domino effect that impacts other components attached to them. This includes hoses, wires and transmission linkages. Therefore, inspecting these components for any signs of damage can help car owners determine if they have a worn mount on their hands. Wires that become taut when the car is placed in drive may also indicate that more than one mount is defective.

Transmission Mount Replacement Cost

Replacing bad mounts becomes a necessity once the above symptoms take hold of your vehicle. The cost of one transmission mount varies depending on your car and the mount brand as well,  but prices usually  range from $50 to $1000. Some experts recommend that all mounts be replaced for the sake of even weight distribution. Failing to replace all parts can have a negative impact on newly  installed mounts in the long run. Installation costs also depend on where you intend to have your mounts replaced.

The replacement process entails raising the engine using multiple wooden blocks in order to safely remove the damaged mounts. The bolts are then  loosened by the  mechanic who  slides under the vehicle in order to remove the mounts that are bolted to the frame of the car. You can save money on transmission  mount replacement by simply getting your car inspected and repaired as soon as you hear or feel any excessive vibration or clunking noises  when you are behind the wheel.

What Makes Mounts Go Bad?

  • Driving Style

Manual transmission can lead to broken mounts due to the nature of this driving style where power breaking before takeoff and over-revving the engine are usually involved. Having more power over the vehicle is great for the driver but bad for the mount in the long run, especially engine mounts.

  • Accidents

Sometimes, fender-benders can lead to minor damage to your car on the outside and hidden damages on the inside. Colliding with another car results in a momentum that can easily cause cracks in the inner gear, including transmission mounts, which is why you need to get your car checked in order to rule out any faulty mounts that can lead to further complications and mechanic repair  bills down the road.

Related Post: 10 Steps You Must Take After a Car Accident

Good quality transmission mounts that are compatible with your car are the key to a smooth and safe  ride, so remember to  keep an eye out for the above symptoms the next time you sit behind the wheel.


  1. Engine or Transmission Mount Replacement Service – YourMechanic
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