Heading out to work today. Got about 1/3 of the way to work. Hit a small hill and suddenly the truck wouldn't shift up. Couldn't go much faster than 30mph. Trying to go faster, the transmission would hunt back and forth like it was going from 3 to 2 and back. 

 

So i pulled over and thought I toasted the transmission somehow. Got to calling around and local shop wanted me to limp it in. 

 

I eventually got to a down hill and it up shifted for me. After that it was okay to drive. Dunno how that happened. But i played it safe and still went to the shop. 

 

The owner put his scan tool on the truck and said my output speed sensor was bad. 

 

So i have him my business and 40 dollars later i had a new sensor replaced by him plus diagnostics. 

 

Of all things it was a sensor that i replaced 4 years ago...

 

So if you happen to encounter the same, maybe start with the sensor...

What brand did you put on there that only lasted 4 yrs?

 

BTW, It is huntin' season

I'm pretty sure it was an oreillys part. So probably Chinese made...