I have a 2000 pontiac trans am an I changed my factory transmission with another factory one an stall (3600 back to factory) an I'm still having the same problems which is it shifts early an hard out of first an i have to get off the gas to make it shift from second into third, an it never shifts out of third. I've changed my engine wire harness an everything, checked all my fuses, swapped my computer with a friends stock one just to see if it was my tune going bad an everything an it still does the same thing. I'm lost an stuck, idk what to do, I'm thinking bout going to a 6 speed cause I'm so pissed an lost. I brought a transmission an mine might not have been bad. My check engine light isnt even coming on so I'm not throwing any codes. can some one please help me out!!!!!!!

 

So no codes? Does the speedo work properly and were both computers programmed for the correct rear end ratio?

 

my computer is but my friend's computer was factory tuned

 

Look at you TPS. It might not be reading correctly and show only part throttle when in fact you are at WOT.

 

will do thanks I'll let you know what happens cause i have an extra 1

 

I changed my tps an my car is still doing the same thing. Im so lost right now, any more suggestions, please help me out with my problem somebody, anybody.

 

So you had a different trans and converter in the car and it had this problem? Then you swapped trans and converter and it still is doing it? Then you swapped PCM's and it's still doing it?
I just wanna verify before I try to give advice

 

Yep it's still doing the same thing idk what's going on. Any advice cause everything everyone has told me to check an change I have, no luck so far!!!

 

Has anyone ever had this problem? Someone please help

 

Just bc you changed your TPS doesn't mean it's right, did you check the voltage? I mean that's really the only thing that makes sense.

 

No I haven't checked it? How would I check it (I'm new to that) what's da voltage suppose to be at? If it's low what would I have to do?

 

I don't know if that would cause the issue you are having, I know it would affect idle. I don't know if it would affect the way the trans shifts. You would probe the wires with a multi meter, you would have to find the "spec" online.
Are you sure that the transmissions were both in good working order?
Are all the grounds hooked up correctly? Did any wires in the harness going down to the trans get smashed, broken, cracked?

 

Yes both trannys were checked and I changed my engine wire harness. I didn't know the trans had a ground cable, where would that be located? I know if da ground on back of the heads aren't tight the car won't start. But where are the ground for the trans?

 

Does anyone know what grounds to check on da car for the tranny

 

does anyone know if there is a ground for the transmission?