overheating, early shifting and high rpms at idle

[dedsmurf]

So here it is.. my poor baby is acting up and I'm at a loss..
Vehicle starts up fine even in the cold (it is New England after all).
Once the vehicle warms up the rpm's are always high.. around 1500+ rpm. If i put the truck into neutral at a light then they slowly go down to around 1000 or so...
Once the vehicle is warmed up and i drive away from a light the transmission shifts early and sometimes with a thunk. i can be in overdrive within 300' give or take. not sure what is happening here. and this morning for the first time the check gauge light came on and the temp gauge was in the red. (doing 60 on the highway and its 30F). I slowed down, the temp went back down but stayed high but not in the red.
I dont know if these are related.
Some data: about 160k miles, oil done every 3k, lucas oil added every time, transmission oil swapped about 40k ago checked and none missing, radiator is hot so hot coolant is getting in (not sure if this helps in the diag), i do a coolant flush beginning of every summer.
Any ideas? I LOVE the explorer and never abuse her.

thanks!
ded

 

[cjp1280]

I am having this same exact problem to the T. These problems must somehow be related to each other.

 

[dedsmurf]

found the issue

thermostat. the thermostat was going and as the weeks progressed the symptoms were getting worse and worse. Then the thermostat blew. once replaced the early shifting were gone, the idle issues were gone etc...
After talking with the mechanic at length the computer was getting incorrect information from the engine temp etc and that was causing all the issues.
its been about a month now.. no tranny issues nothing since i replaced the thermostat. i did a pressure test on the coolant system too.. just to be safe.

dont go to the dealer to replace this. get a replacement thermostat about 15-20$ and do it yourself, about 15 minutes. save 200$.

 

[cjp1280]

Good to know. I was fearing the worst when my transmission started acting up. Amazing how a simple part can cause all those problems.

 

[gijoecam]

Indeed, it's the thermostat. The thermostat causes the overheating, the overheating causes the ECU to bump the idle speed and modify the shift strategy to minimize the heat generated by the trans and aid in the cooling.

Change the thermostat and all will be well again. Make sure you get the new o-ring for the housing too.

 

[dedsmurf]

oh poop.. i just kept on driving until the cooling system popped and then ended up towing to the dealer. mistake! $$$ but that fixed all my issues... even almost fixed my relationship with my wife.. almost.

 

[cjp1280]

Haha - maybe that will have the same results for me!

 

[Clarke]

my "X" is idleing high but thats it once in a while it will shift early but not to often
could this be the same thing but in the early stages? my oil pressure guage is in the normal zone but closer to the low side and i sometimes smell burnt oil inside the truck.