4l60e trans wont shift abouve 2nd gear

[krawczuk]

hi, a friend of mine has a 4l60e , its actually out off a australian vr v6 commodore , has same trans as used in the states there.

but have come across a pretty weird problem.

transmission was shifting fine,.
then first of , he fried 2nd gear , trans was a bit old , he put it behind a turbocharged engine......!!!!.

got trans rebuilt .
will not shift out of 2nd gear .
with harness disconnected it shifts into third.
with laptop connected up and using efi live program ( Download Software) connected up , we can shift VIA the laptop ALL gears ,.
replaced memcal, and computer, solenoids , vss working fine , speedo works.
i cannot figure out why i can make it shift thru every gear thru the laptop , but it wont change normally .

any clues as what could be wrong ?

thanks,
mark krawczuk

 

[gsgns4me]

My first thought is it's losing it's 12 volt power, possibly from a bad ignition switch or open circuit, and the ECM is keeping it in "default shift" until you override it with Scantool/PC.