I am getting a soft whine when I let the clutch out when downshifting on my 04. Wondering if I have a bearing going???

I am running Maxima Extra oil in the trans, but it also happens running Maxima MTL or even Honda's own HP Trans oil, so it is not lubrication related. I have also always run an extra 100 cc's in the trans.

 

I also have an'04 450R and have had no problems with the tranny, even with all the engine mods I have done to it (480 kit, Hotcams Stage II, port and polish head). I still have the stock clutch too!

 

So your not using the Honda syn. moly oil in the transmission ..?

 

Not insulting your inteligence here by no means, because I know that you know your $hi+ when it comes to maintenance, but is there any chance that you have run the drive chain too tight recently?
I havent seen the transmission whine issue on a TRX yet, but have on a few CRFs. They will run their chain on the tight side and things work fine....until they case a jump....loading up the bearings on the counter shaft.

 

The chain has plenty of slack. If anything, it has always been on the loose side rather than the tight side.

And no, I do know better than to run HP4M in my trans!

The whine only happens during a downshift just as the clutch is let out, and you are going against engine compression. If the clutch is let out on an upshift under power, then there is never any whine.