Hi All, this is my first LS (well Vortec) swap and I'd like to make sure I understand the process to get the donor engine running. I have a 4.8L (LR4) out of a 2000 GMC Sierra 1500 4X4, complete with computer and harness (Hdwr 16220610/OS 9381344), I also have a second 0610 PCM (OS 12205612) and a 0411 PCM (from a 5.3L Tahoe) to work with, all (to my knowledge) stock. I built a bench harness having 12V/2A and connect using OBDLink LX. I am using PCM Hammer to read the BIN files form the PCMs, and I have TunerPro RT and UltimatePatcher installed.

I don't plan any mods to the engine, just VATS delete, DTC's, Electric Fan, and maybe Fuel level, but it will be coupled to a 2WD 4L60E.

I started with TunnerPRO, but because I had trouble finding .XDF files to support the OS from the 0610 PCM's I found a BIN for an 2001 4.8L 4X2 having OS 1220832 and a corresponding .XDF file which seams to work.

Then I came across UltimatePatcher which did not require (or has some generic) .XDF or equivalent mapping built in and has the nice feature to compare .BIN files. I was able to load, modify/update/compare the .BINs, and it even generated an .XDF file that TunnerPro could use (although I'm not sure why I would use TP since UP works fine).

So here are my question(s):

1.) Does the PCM care about 4X4 vs 2X4? I don't think it does as some of the 4WD systems were just a mechanical linkage.
2.) Assuming I can make the necessary changes to the PCM in UltimatePatcher should I just stick with the original OS?
3.) Should/if I switch to the 1220832 OS? There are some tables that are different from my base PCM (according to UP), would I just leave it alone since these were probably minor factory tweaks for the 2001 model?

I know these are kind of basic questions and I should just push the write button in PCM Hammer, jut wanted to check here first if there is a preferred path.

Thanks,
Steve