What kind of transfer case oil to use in 91 FJ80?

[JakeVII]

I can't seem to find an answer to this question. What kind of transfer case oil goes in the 1991 FJ80?

I've got that "playing card in spokes" sound coming from my transfer case when I go down hills at 55 mph.
I'm going to do an oil change and see if I need to do the whole case.

 

[IanB]

Same as the F&R diffs, 80w90 API GL5 gear oil.