I have a buddy who put his T-Case in neutral and transmission in park while the motor was running. There was a loud grinding. Why is this? Both components should be disengaged.

 

I've also seen this same thing happen in GM's...

 

i don't have an answer, but i've got a noise problem too.
while in 4-lo, when i get where i want to be, with truck stopped and foot on brake, when i shift into park mine makes a ZINK sound. it doesn't do it in 4-hi or 2-hi. to avoid the noise i turn the truck off, and then shift into park.