techshooter02

I have a 92 gmc truck with the 4l80e trans and i need to find information about the main electrical plug that was updated.

We put a 94 4l80e trans in the truck and the plug is different, newer trans has the updated plug and the truck has the old version on the harness.
the truck has 12 wires in the plug and the new trans has 11 wires.

we took the internal harness out of the old 92 4l80e trans and put it into the 94 4l80e trans and the truck does not shift correctly it shifts very hard and will not stay in OD

So i want to put the origional 11 wire internal harness back into the trans and adapt it to the truck 12 wire harness. I need information about this?? steer me in the right direction please?

Plus i am going to ohm out the VSS to check make sure they are good including the one on the transfercase.

FLT

iTrader: (1)

You can get a kit directly from the dealership that has the plug and the color coordinated directions for what wires go where. IIRC there is are two wires in the harness that have the exact colors with a black stripe. One of those wires are eliminated. I believe the wire was for a temp sensor that was moved to the manifold switch.

techshooter02

I kinda didn't want to spend the much for a harness, seems how the origional from the 94 4l80e is the same harness, i just need to adapt it to my 92 truck harness (cut and splice) just was hoping that somebody might have the color code information needed?

techshooter02

Does anyone know why i am kicking a 85 code from my truck
I have been trying all kinds of things. ohming wires and checking plugs and i can not get it to stop doing it. we even put a new TPS on the truck that didn't help either. It is shifting hard through all the gears 1-2 , 2-3, and goes into od when coasting you have to let up on the skinny peddle to get it to shift
anyone have any ideas, it would be great if you did????

techshooter02

I have checked all my grounds, cleaned them and replaced some and even took a test lead and grounded the pcm box from the batt, before grounding it with test lead with truck running it was 99.0ohms and after grounding it from batt with truck running it was 2.4 ohms

does anyone have any thoughts, help me out
thanks

techshooter02

Well i got a nice service manual now to check whats up with my transmission,
maybe now the weather will be better so i can work on it...so in the mean time i'll just keep reading..

9000th01ss

iTrader: (10)

I don't have a scanner, heres the pic that you need. I put a '98 trans in my '92 C3500. Took me a while to find this picture but it was what I needed.
Got it from a trans shop.

techshooter02

9000th01ss..... thanks very much

techshooter02

took to trans shop and they are charging me 600.00 to repair it.
something about a new internal harness and plug and play to the truck harness to make it work right said he couldn't use the origional 1994 harness and adapt it to the 92 truck harness
hope it fixes it

9000th01ss

iTrader: (10)

Well thats a load of BS.
I took a 1998 trans out of the truck and almost two feet of harness with it.
I used that picture above to splice the wires from the 1998 trans to my 1992 truck together.
That was four years ago, and it's never given a problem since.

techshooter02

well they put in the new harness that they ordered and adapted my 92 truck to the 94 transmission....guess what it didn't work it still is shifting harsh through all the gears. 450.00 dollars later... i asked why my harness from the transmission and the plug from the other truck wouldn't work they said that the new harness they ordered was plug and play.... hhmmm is starting to come to mind.

9000th01ss

iTrader: (10)

Well when I first got mine up and running reverse slipped real bad, shifted harsh in all gears. It came out of a 3500HD which is a 1 1/2 ton tow rig so I thought it was supposed to shift hard.
During the diagnosis as to why reverse was slipping I found out it was putting out 500+ PSI pressure.
Took it apart and the boost valve was sticking, and this trans had 60,00X miles on it. It had no reverse because the high pressure cracked the reverse servo.
I put in a Sonnax pressure limiting boost valve, new rev band, pin and servo piston.

What I'm getting at is you may need to do a pressure check, and look at the boost valve.

techshooter02

trans shop says, when i asked how the presure test went and they said that they didn't need to do it, that it is and electrical problem
they still have the truck

Scottfree

Hey man I got the same issue right now. I'm trying to wire the new external harness to where the old one was i already cut the old plug off I just don't know what wire goes to what. You said there's a picture I can't see it for some reason could you help me out?

FranksCustomTrans

I think this will help https://www.rostrapowertrain.com/wp-.../Form4176E.pdf