When SHOULD overdrive kick in ??

[clubairth]

The TFT needs to see 150 F. or higher to allow the tranny to lock up the converter. I think you are correct that your larger fluid cooler is the cause. Have you removed the thermostatic controlled valve in the fluid cooling loop? These usually fail open and I now remove this completely after talking to Doug L. at FPS. This valve was the factories attempt to rapidly heat the fluid but also have more capacity to cool it off after the initial warm up. The SHO has an extra external cooler compared to the standard Taurus. In cold parts of the country it is common for the ATX SHO to never lock up the TC in the winter.
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[Markus]

The TFT needs to see 150 F. or higher to allow the tranny to lock up the converter. I think you are correct that your larger fluid cooler is the cause. Have you removed the thermostatic controlled valve in the fluid cooling loop? These usually fail open and I now remove this completely after talking to Doug L. at FPS. This valve was the factories attempt to rapidly heat the fluid but also have more capacity to cool it off after the initial warm up. The SHO has an extra external cooler compared to the standard Taurus. In cold parts of the country it is common for the ATX SHO to never lock up the TC in the winter.
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Interesting. I have recently developed an issue with convertor lockup. Let's say the car has completely warmed up and then turned off. When restarted and driven on the highway the convertor locks up in OD as designed. When air temps are below -15C the tcc unlocks after driving at 70 mph for 10-15 minutes. It will lock up again about 10 minutes later. I had thought I may have a failing TFT sensor but perhaps the thermostatic valve is failing rather then the sensor. I get no codes from the EEC. Where in the cooling loop is this valve?


IIRC Ford has a TSB regarding lockup of the tc in cold weather. With my SHO I have always had to restart the car after it has warmed up in order for the tcc to lockup in cold weather. Some say this a a bug in the EEC software.

 

[matt59]

The TFT needs to see 150 F. or higher to allow the tranny to lock up the converter. I think you are correct that your larger fluid cooler is the cause. Have you removed the thermostatic controlled valve in the fluid cooling loop? These usually fail open and I now remove this completely after talking to Doug L. at FPS. This valve was the factories attempt to rapidly heat the fluid but also have more capacity to cool it off after the initial warm up. The SHO has an extra external cooler compared to the standard Taurus. In cold parts of the country it is common for the ATX SHO to never lock up the TC in the winter.
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I hooked up a scan tool for the drive home from work at 4AM it was 50 Deg.
I have been curiuos why the TC takes so long to hook up. I found that mine locked at 115 deg which took abut 15 miles of freeway driving. Funny thing is when it's cold the TC locks up at the exact same spot during my trip home.
I can set my Odometer to the miles I have traveled by this event.
I'm going to try the secondary cooler block method and check the temp before lock up.

My other issue is the long Open loop time but that will be another post.

 

[shoguy3.2]

The TFT needs to see 150 F. or higher to allow the tranny to lock up the converter. I think you are correct that your larger fluid cooler is the cause. Have you removed the thermostatic controlled valve in the fluid cooling loop? These usually fail open and I now remove this completely after talking to Doug L. at FPS. This valve was the factories attempt to rapidly heat the fluid but also have more capacity to cool it off after the initial warm up. The SHO has an extra external cooler compared to the standard Taurus. In cold parts of the country it is common for the ATX SHO to never lock up the TC in the winter.
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Thermostaic cooling valve ??? where do i find this and if i remove it....does the tranny overheat with this valve takin out?? or will it lock up perfetc ...its weird ...my car after warmed up in city driving, it will do 140 KPH at exactly 3 thousand RPM....but after about 20 min to1/2 hour of highway driving in cold wheather, the RPMS gradually increase......last time on the highway ...i was doing 140 KPH doing down the road leadin to the highway ..and i was clockin 3000 RPM dead nuts......after 1/2 hour of highway driving i was looking at about 135-137 KPH at 3500 RPM!!! what the **** guys ??? so where is this valve and what will happen if i remove it ?? i havent touched my car yet...but anything that will help the tranny keep the RPMS down on the highway ..i will try (gas+ more RPM) = me scared of doing damage

thanx for any help guys