Motor oil for the transfer case

[فارس آل سعد]

Guys Ive seen some videos and articles and debates on switching to 5-30 motor oil and people had better experience with it and I got an 05 gmc sierra with the NP246 TC and I live in a extremely hot climate, any ideas if it worked with you guys ? 
 

because I feel it would be better since the motor oil has more viscosity then auto track II and less viscosity of diff oil and of course it’ll get thinner with hot climates but still lubricate better than the recommended manufacture TC fluid, any other ideas before I take the chance? 

[CamGTP]

I honestly wouldn't use anything other than the Auto-trac fluid if that is what it calls for. That fluid is just fine for our climates here is North America, it does get rather hot in Arizona, Texas, New Mexico and Mexico in the summer months, haven't heard of anyone have troubles with that fluid here.