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8.1 swap Wiring

No however I'm sure it's a tcm set of plugs. I've looked up more info and that's where that pic came from after reading. They're plugs for an allison TCM. So where can I go from here? I have a 4l80e and a 3/4 done harness for apparently an allison trans.
 
Well, that sucks!

We'll need to see if your PCM is able to shift the 4l80e to start. If it can, you'll need to find some wiring for the 4l80e then get the PCM programmed to operate the transmission.
 
I guess my idea of selling my 350 tbi complete with engine/harness/computer went out the window lol. I should probably cut off my harness on this one and go that route you think?
 
Looks like that PCM has no trouble driving a 4l80e, just a matter of tracking down a 4l80e connector / harness and replacing the Allison stuff with the 4l80e stuff. Of course, the PCM will need to be re-flashed to run the 80e instead of the Allison.
 
Mountain_man said:
I guess my idea of selling my 350 tbi complete with engine/harness/computer went out the window lol. I should probably cut off my harness on this one and go that route you think?
Click to expand...

I'd get the wiring from a Vortec truck with a similar Vortec PCM, plug and play baby!
 
Little bummed by this setback especially with all the harness work I already went through. I'll look around for another harness I suppose since cheezbay doesn't have any currently.

So 99-04 harness with drive by wire 4l80e is what I want still correct? Just making sure so I know what I'm going to get. :bow:
 
Yup, pretty much! A 6.0L harness would work well... I may have a line on the wiring you need BTW, just need to see if I can find it. I re-worked a 6.0L harness a while back that came with a 4l80e but it went in with an NV4500
 
Not sure if this helps...

The Avalanche was available with an 8.1 and 4L80E. Find a harness from one of those?
 
Did you see this diagram.

fig_13.gif
 
Me I would just start by making the harness standalone for the engine. Then just find a diagram for the 4l80e tranny and add it in. Then just have the ECM flashed for the tranny.
 
Did you find the wiring for alison on lt1swap site? I could surely use out if else where found. I'm going to probably begin this tomorrow. Thanks.
 
Not sure on year tbh. I was told it's a marine spec 8.1. I know it has the 42lb injectors, dbw throttle body. The computer is supposed to be from a 99 -04 from the numbers. Everything for pin colors and locations matches up so I'm saying thats right.
 
Hey im doing a swap to I'm putting the 8.1 vortec in my 87 c10 2wd I'm using the t400 trans I have the doner truck here to 02 Chevy suburban. And I was needing help on figuring out what wires do I give pwr to so I can make this thing run lol any help will be greatly appreciated
 
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