Some routine maintenance got rid of the whine...

[discojj]

Have 67,000 miles on my 01 Disco, finally got around to changing the transfer case fluid. First, upper fill plug was a pain, thing was seized in place, and because of the parking brake, had to use a swivel on a 1/2" breaker bar. Ended up cutting a piece of conduit to use and a leverage extension to break loose. Bottom plug came out easily.... and I was so happy to see barely any metal stuck on the plug magnet (especially after reading some of the horror stories here). Used some loctite on the drain plug and then used Mobil 1 Syn gear oil (using fluid transfer gadget from Autozone, a must). Fill until it started pouring all over me (not so bad, syn gear oil doesn't stick nearly as bad as conventional) then little loctite and screwed the plug in. Before the change I had some very annoying whine @ 70 and also @ slow downs. After the change, just about completely gone. Amazing how much better in cabin sound is..I can actually run w/ out the radio on.

Also detailed and repaired a fog lamp that had a cracked housing (filled up w/ water when it rained). FYI.... drivers fog lamp a pain to remove because of the washer resovoir.

[OkieRover]

Disco JJ
I did the same thing this weekend.
That fluid was burned. Man it was nasty.
And just like you my whine is gone.

I used Castrol though.