Ive got an 05 WRX box which has covered around 35k mls, its developed a whining noise. Stationary it makes no noise whether the clutch is in or out, you cant hear it when travelling along at 20 - 30ish, its only when you build up the speed to motorway speeds it becomes noticeable. It is noticeably louder under load, if you coast at 70 and dip the clutch there is no change in noise level.

Im thinking front diff or transfer box?

 

There was talk of a common fault with WRXs whining at a certain speed (65mph IIRC) which, as far as I know, was never solved. I think most of these cars had the fault from day one, though.

Some people had gearboxes and diffs replaced under warranty without success. Hopefully someone on here knows.

 

I fitted the box at 25k and all was quiet, shortly afterwards I had a problem with the rear diff which wasnt sorted for 5 months, now thats fixed I can now hear this new noise.

To be honest it doesnt seem to be getting any worse but its not meant to be there, Im just wondering if anyone else has had any experience of problems with the transfer box on the 05 box.