You live in Montana, It's cold. I would use 5w30 Mobile1 for oil, ATF+4 in transfer case, Royal Purple Synchromax I hear is really good in the NV3550 trans, I will use it next service, Dino gear lube in diffs, (non synthetic) No Lsd additive unless you have an LSD. Do some searches on here as well as google. Enjoy your new jeep and welcome to Wranglerforum.com :wavey:
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