Outer Limits 4x4 Board

Wondering if anyone can help. Ive got a whine coming from what i suspect is my transfer case (or maybe gearbox) of my 4 speed 40 series. it only occurs in 2nd 3rd and 4th. it gets higher in pitch the faster i go. at highway speeds it is really annoying, you cant even hear the engine (327 chev with 2.5in exhaust) so its pretty loud!
Does anyone have any ideas what it could be? Should I bite the bullet and buy another Gearbox/transfer from a wreckers or could it just be a bearing or seal or something?
any help is appreciated guys, cheers.

sounds like mine... it was the transfer case idler shaft, bearing went.. quite common... i recomend trying to scrounge up another gearbox - tcase combo from somewhere... keep an eye out in the classifieds, alot cheaper than wreckers.

i drove mine for 6 months like it, getting progressively worse till it had so much drivetrain power loss i couldn't maintain speed in 4th...

turbo4t has transfer cases for sale ....you should pm for more info

Maybe get a louder exhaust ??

Thanks for the advice guys. will pm turbo4t for prices. wanted to get it sorted before the springover. The louder exhaust idea deserves alot of thought though.