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Automatic Transmission

The automatic transmission receives power (torque) created by the engine and sends it to the differential. Inside the transmission is a collection of gears that, based on vehicle speed and driving conditions, change automatically in order to keep the engine operating most efficiently.

Symptoms of Wear or Failure

  • Abnormal noise
  • Delayed or abnormal shifting
  • Inability to shift into one or more gears
  • Flashing transmission warning light
  • Illuminated Check Engine Light

Related Repair Advice

  • Vehicles with computer controlled automatic transmissions may have upgradeable software in the transmission control module. Before repairs are made, the repair shop should check and verify that the latest software is installed. Transmission software upgrade information is often found in Technical Service Bulletins (TSBs) from the vehicle manufacturer.
  • What may appear to be a transmission issue may actually be an engine performance problem. A shop should test drive the vehicle and perform a few checks to rule out an engine problem before focusing on the transmission.
  • If your vehicle has over 60,000 miles, a shop may recommend replacing the automatic transmission with a re-manufactured part rather than trying to repair an internal failure. The benefits to this approach are reduced future transmission problems and multi-year warranties on the re-manufactured transmission. Transmission re-manufacturers may also include updates that address the common failures inherent in that specific transmission.
  • Not servicing the transmission fluid at the recommended interval can result in extremely degraded fluid. Servicing a transmission with high mileage and extremely degraded fluid can result in shifting issues after the service. The clean fluid can actually remove varnish build in the valve body. As a result, one or more valves many not seal as well as before the service.
  • It is critical to use the correct fluid type when adding or servicing the automatic transmission fluid

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