Need help with rattle noise from 99 Tahoe transfer case

Hello fellow forum users I just joined but I am having a problem with my Tahoe. I have a 1999 Chevy Tahoe with about 89K miles that has a rattle coming from the transfer case. This rattle seems to be there all the time, in park, stopped in drive, and while driving. I live in the mountains of NM and use the auto 4x4 and 4h on occasions and they seem to operate well. It is a very noticeable noise. At the same time I am also experiencing a vibration that is transmitted through the accelerator petal that happens mainly at 1000 to 1200 rpm while driving only (unable to reproduce when in park). I do not know if these two problems are related or not. The truck is well cared for and fluids are changed regularly. Please help. gold67rs

Hard to think the t-case is making the noise when it's not turning as in park or stopped. I'd be more inclined to think the tranny or torque converter.

Have you had up on a rack to pinpoint where the noise is coming from?

I had it up on jack stands and crawled around under the truck until I located the noise coming from the rear of the transfer case and tale section of the transmission.

Did you put in the right fluid in the transfercase?Use only Auto Trak II fluid from the dealer only.It does not use atf and this started in 1999