Dif and Tcase fluid change

[deserth3]

GM Owners center has added this to the monthly checks. I'm pretty sure it wasn't there before.

Make sure the safety belt reminders light and all your belts, buckles, latch plates, retractors, and anchorages are working properly.
Look for any other loose or damaged safety belt system parts. If you see anything that might keep a safety belt system from doing its job, have it repaired. Have any torn or frayed safety belts replaced.
Look for any opened or broken air bag coverings, and have them repaired or replaced.
Inspect wiper blades for wear or cracking. Replace blade inserts that appear worn or damaged or that streak or miss areas of the windshield.
Silicone grease on weatherstrips will make them last longer, seal better, and not stick or squeak. Apply silicone grease with a clean cloth. During very cold, damp weather, more frequent application may be required.
Check the transaxle fluid level; add if needed.

Damn now I need to crawl under my truck and take a look.