Not really. Had to replace the coolant temp sensor that controls fuel to air ratio

 

You thinking the overdrive is gone?

 

I don't remember the code number it was. But one was 3 to 4 shift malfunction and tcc low voltage

 

Yeah, the high rpm at cruising speed, and only the minor drop with the O/D off button..... But, the PCM should whine about not seeing its RPM drop when it commands Overdrive...... unless, for some reason, it ISN'T actually commanding it.... If the PCM thinks trans temp is too high, it will disable O/D even before the Trans Temp light in the dash comes on. But, that also should turn the O/D off lite on. I think the trick would be, wire a lite in parallel with the O/D solenoid circuit, and see if the light even comes on.

 

Yeah, 3-4 shift solenoid is O/D. Low voltage may not be enough to trigger it. TCC and O/D solenoids both get power from the same source.....

 

Any way it could be the transmission temp sensor? Or anything I can check before pulling out transmission to take it to transmission shop.

 

See if the PCM is actually commanding O/D, as listed above. If you have a scanner than can read live data, see if it will tell you what it thinks trans temp is. Also see what voltage the trans is actually getting. Keep in mind, the trans only gets power for a few seconds at initial key on, after that, only if the PCM sees the engine running.

 

I checked to see if it had power to transmission. And it does. Gave all the connections a once over. Drove it again did the same thing to start with. Shifted it into natural then back into drive everything started working. Shut truck off drove agian everything is working. Don't understand it really. Had one little spot to where you I've it enough throttle to knock down it didn't want to shift again for a few seconds then it work

 

Bad connection? Failing electronics?? Have a look at live data, see if anything seems 'odd'.

 

Did you change the gear for the speed sensor? With those gears it will throw off the pcm. OD is supposed to engage about 45 mph.