4L80E problems

[94_chevy]

Idk if this is the right spot to ask this. So I did a 5.7 w/4l80E swap on my 94 1500. Since I did the whole swap and got it drivable now the transmission doesn’t want to shift, it’ll get 1 hard shift and that’s it. It won’t down shift after that single up shift. I don’t know what to do anymore since im not that experienced on transmissions, is there something I’m missing or don’t have connected right?

 

[88 one ton]

Check the big wiring plug on the left side in the rear to see if its not installed backwards,

 

[Carlaisle]

Are the computer and transmission from the same year? I think there were some electronic changes in the 4l80e over time.

 

[94_chevy]

Check the big wiring plug on the left side in the rear to see if its not installed backwards,

I have it connected with the white arrow on top.

 

[94_chevy]

Are the computer and transmission from the same year? I think there were some electronic changes in the 4l80e over time.

I swapped over everything from the donor truck engine/transmission harnesses including the pcm

 

[88 one ton]

It's in limp mode just got to figure out why.check volts at TPS.

 

[thegawd]

Wild guess... Do you have a fuse inserted in the prndl socket in the end of the dash? Blown?

 

[94_chevy]

It's in limp mode just got to figure out why.check volts at TPS.

Will do, won’t happen to tomorrow tho. How many volts should I be getting?

 

[94_chevy]

Wild guess... Do you have a fuse inserted in the prndl socket in the end of the dash? Blown?

Sorry but I’ve never heard of a fuse like that..

 

[88 one ton]

Will do, won’t happen to tomorrow tho. How many volts should I be getting?

At least .5 at idle