The Basics

Problems with an automatic transmission generally present in one of three distinct ways:

  1. The vehicle will not go at all
  2. The vehicle will roll but will not shift
  3. The vehicle will shift roughly, erratically or unpredictably

The source of a problem with the automatic transmission is not always easy to determine. There are as many causes for problems as there are intricacies to the design. There are, however, ways to hone in on where the trouble is originating and find the cause.

Shifting Problems

Lurching, grinding, failing to shift properly into a specific gear are all common shifting problems. The cause of these difficulties is almost always worn-out parts either inside or outside the transmission. Anything that can cause transmission fluid to lose pressure will create a loss of calibration within the valve body or elsewhere in the hydraulic system and «confuse» the transmission into performing incorrect operations.

It is always wise to check any external connections and look for leaks before resigning to a major transmission repair. Sometimes a problem sounds or feels huge but is, in reality, very small and easily rectified. For example, a weak or corroded battery could cause shifting problems.

Slippage

Suppose you attempt to move your car out of park and into drive but when you do, and then attempt to move forward, the car just revs but goes nowhere. All of a sudden it lurches forward and thumps into second gear. That is a clear sign of transmission slippage. It wasn’t until you reached those high RPMs that the governor gave the signal to shift into gear.

Problems with slippage also tend to originate with worn parts or leaks which lead to mis-calibration of fluid pressure, but more commonly they appear due to low fluid levels. This is why it is important, even with a new transmission, to check fluid levels often if your vehicle features an external dipstick for this purpose.

If you cannot find your vehicle’s transmission fluid dipstick, consult your owner’s manual for its location. Many newer models, particularly those with Continuously Variable Transmissions (CVTs), may not have a way to externally check fluid levels and are self-contained. With these vehicles — barring leaks due to impact or other external forces — you may need to seek the aid of a mechanic to properly diagnose the issue.

Abnormal Noise

If your vehicle’s transmission is operating normally, it should not be notably noisy. If you experience clicking, grinding, whining or buzzing noises as you are driving, seek the aid of a mechanic as these could be minor problems, escalating problems or ones that could threaten the continuing proper operation of your vehicle.

Play it Safe

As with any automobile problem, it is never wise to ignore or attempt to justify anything that feels or sounds out the ordinary. If something doesn’t sound right to you, trust your instincts and have the problem diagnosed. It could mean the difference between a small repair bill, a very large bill or the total loss of use of your car.