Odd.
The noise my pinion made was as noticeable in neutral / coast as it was in gear... so load did not play a role there ( at least, not an audible difference to my ears ).
Furthermore, the only culprit was a single "pit" which was no bigger than the size of a pinhead and the depth was little more than a surface scratch - everything else looked pretty darn new, and to this day I am still amazed that negligible defect alone could have caused all that jet engine whine... but it did.
So, provided it is your pinion I wonder if it's another type of damage ( not pitting )
...a heat warped surface ? which might manifest itself with different symptoms, where in neutral you escape just enough load and friction to mitigate the noise ?
Not sure how easy it is to find someone locally who has done pinion jobs on 968s so as to diagnose this with confidence - that would be the ideal way to handle it.
( most dealers have no clue and are unwilling to offer a money-back guarantee if they do the work based on their best guess that it's the pinion, and then much to your dismay you realize something else may be the source of the noise.. )
But.. at the proverbial "end of the day"... a distinct JET ENGINE WHINE sound =
99% probability of a bad pinion bearing according to personal experience and the significant amount of time I spent checking with multiple sources, mechanics, etc.. However, this is too much $$ to risk relying on subjective based factors such as sound, subtle differences in different gears, etc.. A stethoscope and a professional ear ( as Dave suggested ) is definitely indicated.
