GM Service Manual Online
For 1990-2009 cars only

When carrying out troubleshooting of the automatic transmission, check the transmission in the vehicle first to find the root of the problem, and then determine whether the transmission should be dissembled or not. Neglecting to follow this procedure will result in wasted time and may cause secondary problems. Automatic transmission problems are categorized as follows:

  1. Improper inspection or adjustment
  2. Poor engine performance
  3. Failure of hydraulic control mechanism
  4. Failure of hydraulic control mechanism
  5. Failure of electric control unit
  6. Mechanical failure in transmission

In order to properly diagnose the problem in the vehicle, try to determine as accurately as possible from the customer the nature of the problem. Try to reproduce the problem if possible.

Technical interview

The first step in the troubleshooting procedure is to assess the conditions which prevailed at the time the conditions when it continues at the acceptance. However, when the problem disappears. It is difficult. If the problem can be reproduced, action can be taken immediately. If not, every effort should be taken to reproduce the problem as closely as possible before proceeding. Even experience service personal may make errors or come to a standstill if troubleshooting is carried out without first trying accurately reproduce the problem, For example, a problem which occurs only in cold weather or when the vehicle is at a stop. Therefore, to reproduce the problem, it is important that the customer should be asked for detailed circumstances which lead to the problem: this is the "technical interview". As the information gathered in the course of this interview is discussed in troubleshooting, it is necessary not only to ask a series of questions but also to suggest what factors may have had a bearing on the problem, it may be helpful to create a check-list which could be used in such interviews.