Overdrive light blinking - Diesel Forum

Martlee3 · 04-25-2005, 10:38 AM

Hi,
I have a '97 automatic tranny and it has an intermittent problem. Seems about every other day for the last two weeks. The overdrive light on the shifter blinks and the tranny shifts kind of hard between the gears. Seems to be getting to happen more often and last longer as the time has gone along. Fluid is good and when light isn't blinking, it shifts great. Any help would be appreciated.

Marty

Casey_1 · 04-25-2005, 10:53 AM

The flashing OD light means the computer has found something wrong with the transmission. It could be the trans, wiring, or a sensor. You need to have the code(s) read to find out what it doesn't like. I think the '97 requires an OBDII scan tool, but I'm not sure about that.

JOAT · 04-25-2005, 11:15 AM

Welcome!
Till you can get the codes read, you can check the Torque Converter Clutch (TCC) for slipping. Hold a steady speed on the highway, then vary the throttle up and down a bit. RPM should stay locked to vehicle speed, if it goes up and down while at the same speed, the TCC is slipping. Another test; hold a steady speed, and tap the brake while keeping the throttle steady. RPM should jump 200-400, then drop back within a second or two of releasing the brake. If it barely or doesn't jump, the TCC is slipping.

Martlee3 · 04-25-2005, 11:16 AM

Thanks Casey. I guess it is time to have the mechanic look at it. Was kind of hoping it was a simple answer that I could fix but knew better!
Marty

GOPDiesel · 04-25-2005, 11:37 AM

Good luck. I also have a 97 and am dreading the day this happens to mine. If money wasn't an object, I'd upgrade before I had a problem.

Pat

Casey_1 · 04-25-2005, 01:00 PM

It might be something really simple, but until you know the code(s) all anyone can do is guess.

Seafarer12 · 04-25-2005, 01:47 PM

Take it to someone with one of the fancy scan tools. They can pull up the tranny codes. A cheap scan tool won't do it. Hopefully it is somehing easy. When mine did it, it cost me 2300.

04-25-2005, 04:06 PM

Martlee3 · 04-25-2005, 07:05 PM

Thanks for the help guys. It indeed was what Joat thought. The Torque Convertor Clutch slipping. Looks like it is time to spend some money!!! Have 155,000 miles on it and pull a lot of weight daily so I guess it is time. Once again, thanks for all the responses. I am in the Denver area. Not sure how to fix my profile so it says that.
Marty

StorminNorman · 04-25-2005, 09:55 PM

Up there in the header is a link to "My Home". That contains your personal information and a box for you to enter a signature line. Just type your vitals in there and it will show with every post.