I have a 94 12 valve auto. it will shift fine to third then the trans temp light will come on and never shift to 4th and over drive then the light will go off and it will shift up. Then randomly come back and down shift to third. Fluid is fine. Any help would be great!

 

Sounds like your transmission temperature sensor.
Does it make a difference if your truck is cold or warm?
DD

 

Possibly TPS?Just look at some more threads,somewhere on here someone has had the same or similar problem

 

could also be a plugged cooler/heat exchanger ..... might wanna trouble shoot more ... possible flow issue ...

 

How would i go about troubleshooting the cooler?

 

need to see if any fluid is getting through the cooler. not sure what the pressure should be through it but it might be a good idea to change the filter and get some new fluid in there, make sure nothing is clogged up. have you pulled the pan since this started happening?

 

Fluid is alright, it was a bad trans temp sensor.

 

as i figured ... something silly

 

Heck yea! That's good! Cheap easy fix!

Sent from my GT-I9300 using Tapatalk

 

Heck yea, 25 bucks and like 5 minutes took longer to crawl under and back out of the truck than it was to put it in!