when my truck is cold it does not want to shift into overdrive. I have to let off the fuel petal at 55 to get it to shift. Then if I get back on it sometimes it will shift right back to third. Once the motor warms up some the tranny shifts fine no problems at all. What do you guys think.

 

How cold has it been round your place lately??


There is a tranny temp sensor that is on the tranny line right next to the tranny pan (drivers side off the front line)

This might be getting an inaccurate reading.... or its accurate and the tranny fluid isn't up to temp and its holding out od until it warms up.

 

in the morning it has been like 60 or so. I thought that the sensor was only for high temp od cutout.

 

The sensor on the 1st gen's is a temperature switch set to open around 250-260*F. 2nd gen's have the temp sensor

Your right the sensor is really just a switch.
I think there is a coolant temp min, but I think the magic number is 66* and it gets there pretty quickly.
Most likely problem is the TPS and when the engine bay gets warm it starts to behave again. One of mine does it and still does it, I put a manual switch in it, I still haven't dealt with it. Only does it in the cold anyway.

 

What he said. You were over the minimum coolant temp 2 minutes after you lit the fuse.

 

I know it is not good but I usually do not let it warm up before I go down the road. I usually have it in drive before the starter has stopped turning. tonight when I was leaving work I let it run for 5 minutes and there was no od issue it went right in.

 

It's better for the engine to drive it gently than to sit and idle.

 

I would also bet on the TPS. I've had similar symptoms as well. I've been nursing an intermittent one for some time now. At the beginning, I thought it might be temperature related but that turned out not to have any thing to do with it. The TPS is quick to take off and fiddle with. Several months ago I took it off and tried to force some tuner cleaner in around the shaft then exercised it for quite a few turns back and forth. It's been working fine ever since.

 

I will have to try that.

 

Good timing on this thread...
This is my first auto, and i dont know much aboutthem..
Mine has just starting doing this exact same thing... wont shift up into OD until the tranny temp gauge is reading around 140 or so....
So the likely culprit is the TPS
or could this be a shift down cable adjustment problem also?

its just started dropping down into the 60's and a few 50* mornings ... starting to see a lot of haze onstart up as well...

 

Yes, TPS is the most likely culprit.
No, the shift down cable only affects gears 1, 2 and 3. 4th or Overdrive is controlled by the PCM via a solenoid in the valve body, through many inputs such as speed, TPS position, coolant temp, and the transmission temp switch in the hot line.

 

Thanks Mike.. reading teh stickey now on teh TPS adjustment

 

OK, pre-adjustment I was at 0.26 VDC at rest and 1.7 at WOT...
Now at 0.8 at rest and 3.79 at WOT.. hope this helps!!!

 

I love the search function. I knew I had seen something on this before and my truck is doing it now.