02 avy swap help needed

glsawyer · Sep 14, 2025

So im dropping a 01 6.p and 4l80e into my 02 avy. Ive read that I use my intake, harness and accessories. I have the 6.0 computer. Is it a plug and play setup? Or do I have to get my computer tunned and run that?

Also will my headers still fit?
What needs changed to run the 4l80e? I do also have the tcase for the parts rigs.

stutaeng · Sep 14, 2025

What years are the vehicles? If both are Gen III-based vehicles:

1. Best to keep your intake and ECU, just get a reflash for the new engine/transmission.

2a. You need to swap your T-case input shaft that fits the spline pattern of the 4L80e. Or

2b. Swap a NP246 that was already mated to a 4L80e such as from a Suburban 2500.

3. LT1Swap.com has information on the wiring harness pin out swap for the 4L80e conversion. It looks difficult but it's not.

4. You may need driveshaft shortening/extension due to linger transmission? I'm not really sure on this actually. My swap was a 2wd...

glsawyer · Sep 14, 2025

stutaeng said:
What years are the vehicles? If both are Gen III-based vehicles:

1. Best to keep your intake and ECU, just get a reflash for the new engine/transmission.

2a. You need to swap your T-case input shaft that fits the spline pattern of the 4L80e. Or

2b. Swap a NP246 that was already mated to a 4L80e such as from a Suburban 2500.

3. LT1Swap.com has information on the wiring harness pin out swap for the 4L80e conversion. It looks difficult but it's not.

4. You may need driveshaft shortening/extension due to linger transmission? I'm not really sure on this actually. My swap was a 2wd...

Ok. Im planning to use the engine/trans and tcase from the 2500. It was a 2000