Engine & Transmission Mounts

When an engine or transmission mount is worn there are often symptoms that indicate there is a problem. The most common symptoms are:
  1. Increased engine noise and vibration.
  2. Binding of linkage: i.e. throttle and transmission controller linkages. The typical symptoms are increased pedal pressure or slower response to driver inputs.
Consequences of a worn or damaged engine mount:
  • Jammed throttle linkage, resulting in unintended acceleration.
  • In extreme cases a broken mount may cause the engine to rotate forward and puncture the radiator with the fan blades.
  • Excessive engine "rocking" can also create dangerous exhaust leaks where the head pipe joins the exhaust manifold.
  • A failed mount will also contribute to exhaust system rattles.
  • Excessive engine vibration can damaged exhaust doughnut seals in the exhaust joints or cause an exhaust flange pipe to crack or break.
  • Worn or broken engine mounts also place added strain upon the transmission mount, which can lead to misalignment of the driveshaft which can cause the transmission mount and/or the universal joints to fail.

Suspension Strut Mounts

Worn or failed suspension strut mounts can cause the strut and the strut tower of the chassis to move independently of one another which will result handling and ride-quality problems.

The most common symptoms are:
  1. Clunking or creaking noises from the strut area
  2. Steering memory problems where the vehicle will not return to center after a turn
Consequences of a worn or damaged suspension strut mount:
  • Poor handling performance
  • Premature or uneven tire wear
  • Vehicle will continuously drift left or right
  • Damage of the strut assembly causing drivability issues

Technical Tips - A Quick Check Diagnosis:

Note: all engines rotate slightly opposite to the direction of the crankshaft rotation. Have an assistant start the engine and apply the parking brake. While still applying the brakes, put the transmission in gear (drive) and slightly increase the engine throttle. A severely worn or broken mount will cause the engine to show excessive movement, sometimes as much as several inches. Next, check the mounts on the other side of the engine. Once again have an assistant start the engine and apply the parking brake. While still applying the brakes, put the transmission in reverse, and slightly increase the engine throttle. Look for excessive engine movement on the other side.

Suggested Preventative Maintenance:
  1. Whenever the engine and/or transmission are removed for service, the mounts should always be replaced.
  2. Inspect the condition of the mounts every time a vehicle is on a lift. It can solve potential serious problems and repair down the road.
  3. Leaking hydraulic fluid from a mount indicates a hydraulic mount has failed, and must be replaced.