Mechanics

O/D LIGHT BLINKING AND THEN SERVIC

2003 Mercury Mountaineer

Transmission problem
2003 Mercury Mountaineer 6 cyl All Wheel Drive Automatic 99000 miles

While traveling up a sharp incline at work this week, my O/D light started blinking. The vehicle would not move either. I put it in park and tried again and the light stayed on blinking and the vehicle would still not move. I put it in park and shut the engine off re-started it and the O/D quit blinking. I could then proceed up the hill at that time.

This happened two days later. Same thing my O/D light started blinking. The vehicle would not move either and then Service Engine light came on. I put it in park and shut the engine off re-started it and the O/D quit blinking but the Service Engine light stayed on. I could then proceed up the hill at that time.


I had the code read and there was only one. It said " speed sensor"

I just had the transmission replace about 7,000 miles ago. The vehicle was jumpung in and out of O/D before that and the mechanic said I needed a new transmission. It still does not drive right. It slams into gear quite often when shifting from neutral to reverse and it still seems to jump in and out of OD occasionally.
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Rickburkett
January 23, 2009.




The speed sensor can cause the problem, but if you only have 7K on the new trans, I would think it is under warranty.

Is the speed sensor on this vehicle normally part of the transmission replacement and therefore it should be covered under warranty?

Tiny
Rickburkett
Jan 30, 2009.
Hi:
The speed sensor isn't part of the trans. Here is a schematic of how it's wired into the system. If this isn't the problem, I would be in touch with the rebuild company.


http://www.2carpros.com/forum/automotive_pictures/249084_speed_sensor_1.jpg



I hope this helps.

Joe

Thanks Joe, Can you tell me where the VSS is physically located on this vehicle.I am an electrician. Should this be simple enough that I could change it?

Rick

Tiny
Rickburkett
Jan 30, 2009.
Ok, I was able to locate 3 different ones. Although it's not part of the trans, there is a VSS out put on the top of the trans. Here is a picture of one and its location.


http://www.2carpros.com/forum/automotive_pictures/249084_trans_1.jpg



There are two more on the transfer case for the auto 4wd, but I don't think this is the problem. Here are their locations and pictures. Both are on the transfer case.


http://www.2carpros.com/forum/automotive_pictures/249084_sped_sen_1.jpg




http://www.2carpros.com/forum/automotive_pictures/249084_speed_1.jpg



Let me know if this helps. The one on the trans will be hard to access. That is the only problem I see, and I think that is the one you want.

Let me know if this helps.

Joe

Thanks again Joe

You refered to a VSS on the top of the transmission but none of the three in the top drawing are specifically called a VSS. One is the turbine shaft speed sensor, one is the intermediate shaft speed sensor and one is the output shaft speed sensor. Is the VSS you refered to one of these?

Tiny
Rickburkett
Jan 31, 2009.
I spoke with another mechanic and he said it's the one on the rear of the transfer case.

Let me know how it works out for you.

Joe
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