On Craigslist there is a listing for a 1999 6.0, with harness and computer mated to a 4l80. Since I have a 99 with a T56, the computer would be able to control the transmission, as long as I have it re-flashed as a truck, correct?

Now for another question....could another option be to buy both the computer and 4L80 and switch out the truck computer with mine?

all replies appreciated!

 

yes that is correct, You can reflash your PCM to work. 98's also work now with some mods.
run your own PCM and you will be good to go.
Im in the middle of this swap on my 98 and its not so bad.
my 98 PCM will be reflashed with the stock 4l60e trans file and it will control it that way.
good luck

 

Good news. Now if I were to buy the Silverado computer with the 4L80, could I swap computers and not need a tune? (or not spend cash to buy hptuners)

 

is this going in your Z28? I would just have someone reflash the PCM, that is not too expensive and you will keep all the stock harness intact. That is the route I would go, I think its the easiest too.
Im not sure if the harness from the Silverado and the Z28 are the same...there are more than the engine and trans control that matters....but Im not too sure about what all you need to do if you wanted to go that route.

 

I would go on the HP tunner website and post it on there. Or pm a sponser tunner on here. I know I had a buddy put a 2002 computer in his 98 trans am and had to splice a bunch of wires and looked like a nightmare. He put the newer computer in so he could run a 3 bar and run more boost on his turbos.