Truck transmission rpm doesn’t downshift

Hello, my name is \*\*\*\*\* \*\*\*\*\* welcome to just answer! I will be assisting you with all of your vehicle questions today. I’m really sorry that you’re having this issue and I’m going to help you through it, but please understand that I (respectfully) don't know your skill level or tools you have to assist us to diagnose/repair your vehicle. Also, understand that I can't see, smell, hear or touch the vehicle either, so your patience/understanding is appreciated. I do not know anything about the fees or charge so please if you have any concerns, direct them to customer service. You will be automatically offered a phone call by the website, which I am not personally able to complete. A phone call is not necessary or required and you can ignore the offer if you wish. The trans does not Down shift or Upshift?

It upshifts

so im assuming when your slowing down the engine stalls ?

Yessir

What codes do you have in the computer?

No codes just a evap code

any other history to this issue? did it just happen out of no where?

I Juss got it out the transmission shop new tranny in it because mines was all cracked and no goodit’s Juss been only up shifting from take off that’s it doesn’t switch out of 1st to 2nd to to third

mmm ok why are you not taking it back to them for them to see what they did or not install or gave a bad tranny or converter ?\>

This needs to go back to the people you got the trans from /installed. they will have the scanners to see what's going on with the unit that was installed and under some sorta warranty.