ok my dad just got done rebuilding my 4l80e he rebuilt automatic transmissions for a living for 15 years but that was when 4l80es were just starting to come out so he does not have a lot of expereance with them. it has a new circle d multi disc converter , all new alto red rebuild kit with kolene steels , anti walk out case bushing and transgo hd2 kit . I wired it up externally according to the sloppy wiki page instructions for it to shift full manual and now that its together it has no reverse , the lockup does not work when I ground the wire , 1-2 shift is great but 2-3 and 3-4 is weak and seams to slip under a lot of power on those shifts . I took the pan off and all the wires are getting power so I tried gounding all the shift solenoid wires and pressure manifold wires and that just locked it in 3rd. i sm not sure if its the trans or the wiring but i wired it up exactly how i was supposed to any guesses would be greatly appreciated. it is a 83 ltd wagon with gen 4 4.8 twin 59mm garret turbos running on microsquirt. 2000 model 4l80e thanks

 

Reverse is a totally mechanical function so not wiring related if you have no reverse its either an issue with the Low / Reverse band or the direct clutch mechanical .

 

did you measure the reverse pin for proper engagement, reverse failure is very common in 4l80e due to that as well as the reverse band itself. he should if installed a new reverse band during install as well and made sure the drum did not have escess wear. jakes performance has a how to in setting up the reverse band and rod clearence.