[Squishy]

I was under the car recently and noticed a slow leak from the transfer case output seal. At 190,000 km (~120k miles) I'd like to change the fluid for both the transfer case and rear diff.

Are there specifications available for type of fluid and fill instructions?

 

[C&C]

It is on page 11-13 of your service manual. Transfer case all wheel drive: Transfer case fluid GM Part No. 19256084, in Canada 19256085 (can't help you on fill instructions)

 

[Squishy]

That's all I've found so far. Nothing seems to list the rear differential fluid nor are there fill instructions. "Lifetime" fill doesn't apply if all the fluid eventually leaks out...