Transfer Case Fluid

[Rhett59]

I am going to replace the chain in the np271 as it is stretched. I have a buddy who runs 80W-90 Lucas with Lucas HD oil stabilizer instead of ATF+4. I was wondering are there any benefits / downsides to doing this? I'm contemplating running 80W-90 because this is the 3rd time this chain has stretched in the past 3 years.

Any help would be greatly appreciated!