Questions and Answers

Mitsubishi Galant Overdrive Problem Q. I am currently having a problem with my Overdrive. When driving normally with the overdrive switch "ON" It will not shift from second gear to third, and if it does it won't actually be in gear, engine RPM just races up. But when the overdrive switch is "OFF" and the car is in DRIVE, the transmission shifts fine.

When about 55 MPH in DRIVE, if you try to turn the Overdrive back on it goes back out of gear and engine races again. When overdrive is turned back "OFF" the transmission goes back into gear and drives fine.

My question is, can this be caused by a bad Throttle Position Sensor (TPS)? I have done extensive research on this and have found much mention of this little sensor when related to shifting problems. I thank you for all of your insight and help on this matter.

• 1996 Mitsubishi Galant
• 2.4 liter, 4 cylinder
• Automatic transmission

Sincerely,
Sara
Andrews AFB, MD

A. The TPS will cause erratic or no shifting, but it will not make the transmission slip, which is what yours sounds like it's doing.

The Transmission Control Module will store codes. You will need an analog voltmeter to access them. Here's how it's done.

Connect a voltmeter to terminal (4) and) terminal (6 of the data link connector underneath the instrument under cover, and take a reading of the diagnostic trouble codes from the movement of the needle on the voltmeter. A long needle sweep indicates tens and short needle sweeps indicate ones. So: long sweep, long sweep, short sweep, short sweep, short sweep, would indicate a code 23.

If there are no codes stored, then it is a mechanical problem inside the transmission.