Nope, I reckon you got it smack on. The issue must be with one of the bearings on the layshafts that the driving gears are mounted to.wagonist wrote:Anyone disagree?
What speed/speeds does this noise appear?
There are needle bearings but they're on the other part of the low range setup:

(left one is the L series unit) This is the other gear that completes the low range system, the shaft it's on has the needle bearings but these wouldn't be under load in high range, thus wouldn't be making any noise.
I'd be looking at other bearings or other things on your subi to solve what it is.
If you can give us more information about speeds/engine loads when the noise occurs that would be helpful too.
Cheers
Bennie