Hearing grinding is it transfer case?

[keithchandler13]

I have a 1998 GMC Yukon 5.7l 4x4 When I engage 4x4 the grinding gets really loud when I drive, but when I take it out and put it in 2hi I can still hear the grinding, it is not as loud though, I think teeth are missing on gear. Is it hard to replace transfer case and how much and I looking at? Do you think the fluid may be low? How do I change out the fluid?
Thanks Keith

 

[SunlitComet]

A swap for a remaned unit may go from $500 to $1200. For more data tell me, what t-case do you have?

 

[Donnie Yukonie]

maybe the front dif? putting power to the front dif might be makin it worse maybe y its gets louder when 4x4 is engaged just a thought?

 

[strad]

All the diffs and transfer case have fill plugs. Remove those with the truck level and see if fluid drips out (or pours out) if no fluid comes out then the fluid is low, and you'll need to add some until fluid starts running out. Then cap it. edit: low fluid can cause noisy ops. That's why I suggest checking it. Low fluid can also destroy things, so it might already be too late if low fluid turns out to be the cause of your noise.