I'm looking through the 2018 Owner's Manual for my 2018 Silverado 1500 LT 4x4 (NOT Z71) and there are 2 different maintenance intervals for changing the transfer case fluid. With a GVW under 8,600 lbs it should be done every 97,500 miles. With a GVW over 8,600 lbs the change interval goes to every 45,000 miles. I guess the cover of the owner's manual DOES just say "Silverado" and not 1500, as I didn't think any 1500 had a GVW over 8,600 lbs. Assuming they are referring to the GVWR (Gross Vehicle Weight RATING) which for my vehicle is listed at 7,200 lbs.
Are the fluids really THAT good now? 97,500 miles? I plan to drive this truck until it drops so I guess I'll find out. And maybe they are that good now. After all the manual (on Page 446) also says I can go for 150,000 miles without changing the cooling system fluid. (Would almost seem demeaning to call the stuff just "antifreeze" these days if it lasts THAT long.)
Silverado 2018 Owners Manual.pdf