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2000 7.3. 176k miles. 4WD. Original owner. Original tranny. Limited yearly towing since new.
Local Ford dealer replaced drive shaft U-joints due to vibration/frozen rear joint.
First time at highway speed next day noticed overdrive will not engage.
Usually ~2100 revs at 70 mph........now over 2500 revs at 70 mph.
Tranny hit 190° with ambient temp of 60....usually always 90° over ambient temp.
So far no other symptoms such as speedo failure, low charging voltage, etc.
OD cutoff button on end of gearshaft lights when pushed, but no rpm change when pushed in or disengaged at speed.
Tranny fluid and filter change a month or so ago with Ford Mercon V....(label sez Mercon compatable.....). Fluid full and regular red color.
Obviously going back to dealer to read codes, etc. but what are the best places to start?
OD wires in shifting column?
Speed sensor rear end and/or tranny?
Something jostled with effort required to remove frozen U-joints?
Merely very weird coincidence?
If it's hitting that temperature that high of a temperature, you either have an obstruction of the cooling lines or the bypass valve is stuck open. My understanding is that there are bypass valve rebuild kits and they don't seem too complicated or time consuming to rebuild.
Usually ~2100 revs at 70 mph........now over 2500 revs at 70 mph.
That's not enough RPM change for it to have shifted out of overdrive. If it was turning 2100 RPM in overdrive and shifted to third gear the RPM would now be 2958 RPM, essentially 3000 RPM. Since you are only seeing 2500 RPM your problem is that the torque converter is not locking, but it is shifting to overdrive. This would also account for the higher temperature, since an unlocked torque converter makes A TON of heat. RUnning in third gear instead of fourth gear will not make much, if any, change in transmission temperature.
Maybe way more.....It would not make it to overdrive, regardless of how hard I pushed it (I briefly hit almost 3k revs, but quickly backed down when it was clear that overdrive was not along for the ride).
The lower gears all shifted as expected....just never made it to overdrive.
Maybe way more.....It would not make it to overdrive, regardless of how hard I pushed it (I briefly hit almost 3k revs, but quickly backed down when it was clear that overdrive was not along for the ride).
The lower gears all shifted as expected....just never made it to overdrive.
It was as if the OD button was pushed in.
Is this a more fulsome description?
Get the codes. Without codes it's all guesswork.
If you get an OBDII adapter (~$25) and Forscan (free!) you can use a laptop to read all of the codes yourself. That's probably a lot less than a dealer will charge you to read the codes.
What does Forscan show as the gear ratio across the trans when it thinks it is in fourth gear? If I remember correctly the parameter is called gear_rat.
