Mustang GT Overdrive - Ford Forums

AED71 · 07-10-2003, 01:05

Hi,

It's again me with my new question about O/D. I'm not using my Mustang too aggresive thus I generally prefer to drive O/D ON mode. However, on the highway sometimes, esp. while passing I prefer to switch to O/D OFF.

My question is, after using O/D OFF mode for a while, although I do not push the O/D button again (to turn it ON), it automaticly turns to O/D ON mode. Is there a mechanism that automatically turns the O/D ON when you start driving quietly? Or is there a fault on my O/D system?

Thanks
AED.

big1 · 07-11-2003, 07:35

If your refering to your 97 Mustang yes there is the possibily that it can switch into o/d without you doing it. If the car was built for California use this option was installed as per state requirement's, or you aquired a vehicle that when being assembled got the option by mistake.
When it does this (goes back into O/D) and you cruise for awhile, then go to pass someone does it function properly?
If so no harm will be done.

AED71 · 07-21-2003, 01:29

Hi big1,

I have tested the O/D last week and during weekend after your comments. However I could not observe the conditions when this occurs, I know that it is not related with rmp or speed. Friday morning while I was going to work, I switched to OFF mode and during 30min it did not goes to ON. So I am a bit confused.

During weekend, I tried to pass many times but it did not goes to OFF mode again. In general the passing performance is very good so there is a possibility that I could not get the difference between two modes. However it's for sure that the green light does not show that it turn to OFF.

As a result, I gave up testing the O/D and I will contact the service. I appreciated your comments and help. By the way, I don't think that it's built for California, I'm from Middle East. It should be from New York or that region, California is very far away!

big1 · 07-21-2003, 05:21

Califonia built doesn't actually mean that it must go to California. It's just a build requirement. Different requirement's at the time of it being built. California's law's are stricter, but the unit's can be shipped elsewhere.

08-21-2003, 14:47

I cannot speak to whether all GT's had this feature. What I've observed in my own '96 is that the overdrive turns on again at approximately 65-70 miles per hour when driving at a constant rate. I say from 65-70 because I have some modifications that make the exact speed hard to pin down, i.e. 4.10 gear, oversize tires and different speedo gear. I can however say that it happens at the same exact reading on the speedometer consistantly. I have not been able to tell whether that is also the case while accelerating hard through that speed. It does turn on again at some point when accelerating hard, possibly at a higher rpm and shift point. Also, it does not turn off again until you press the button again and it will not turn off if I am driving above that speed.

My conclusion would be that if you have this feature, it is exactly that - a feature, not a defect.

08-22-2003, 14:52

As a P.S., I played a bit more today and found that the overdrive off light does go out when accelerating through the speedometer reading on my reply of yesterday. It does so at exactly the same reading on the speedometer, even though the car does not shift until well beyond that point.

AED71 · 09-05-2003, 02:19

Thanks chsmdwn,

I didn't happen to me, anyway. In fact the performance of engine with overdrive is much more than I (usually) need. I wonder if the 0-60 performance (which is 6.7sec for my 97 GT) is with overdrive on or off? I also wonder how much is the fuel consumption change without O/D? I mean are those datasheet values with or wo O/D? Any idea?

big1 · 09-05-2003, 06:06

Fuel consumpion data isn't taken in a vehical. The standard's are achieved by running an engine on a test stand at a set RPM. The rate of flow is then factered in given a set vechical weight and gear ratio.
Ford Motor Company is starting to use information obtained from "Dyno" reading's and releasing this to the public. It isn't being recieved very well because it appear's as though the vechical has worse milage.
The public want's to believe their vehical's are getting good milage . They don't want reality.

AED71 · 09-08-2003, 05:37

Thanks big1.