Need help "flashing" a 8.1 tcm file into a dmax tcm

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I come from the LS1-LSx world so this Allison TCM stuff is very new and foreign to me. I am dealing with a bone stock 2002 2500HD 8.1 4x4 that is having TCM issues (at least I think it is). I cannot find a reasonably priced 8.1 version TCM to swap in, but I do have one from a 5 speed Dmax Allison sitting in my hands. My question is this, what is involved to put the 8.1 tcm file into the dmax tcm? Both tcms look identical and have a model # 29537441 on them so I assume they are identical as far as hardware goes.

Can I simply install the TCM into the truck and flash everything with it's stock tune for the truck, therefore putting the stock 8.1 Allison TCM info into the "new" tcm??? I have read on this forum that EFILive only touches a very small % of the TCM info, only the trans info that is stored on the ECM itself. So I am worried if I just flash the truck with it's own file that it will not put all the needed info into the swapped TCM.

Am I over thinking this? This is a daily driver and I don't want to destroy anything. Thanks for your patients with this Alli-noob.

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Also, I have tons of available trans VINs that are unused because I normally only work with gen III gas engines. I read somewhere that I can use one of these available trans tunes to do this, is this true or not???

[LS-SWAPPER]

The more I read, the more I think these were stupid questions...