Anyone know if I can put a transfer case from a 2001 Yukon on a 99 Yukon Denali?

The Denali was a all wheel drive and the standard yukon was push button with low range. Not the same at all.

The Denali isn't AWD. It'* push button with hi/lo range.

Sorry, I didn't notice it was the old body style denali. after 01 the Denalis were AWD. I checked rockauto.com and they list it as the same part number if it'* electric shift so I'm thinking its the same transfer case. The only difference might be in the shift motor assembly but that is easy to change with the transfer case out.