[kiwidog]

IMHO much of the gear whine in a one piece transfer case can be traced to a worn bushing in the high speed gear on the TC output shaft.
When the transfer case is in high range this doesn't turn on the shaft it turns with the output shaft as it is locked onto the shaft by the range selector collar The low range spins freely on the shaft when high range is selected.
Even though high speed gear doesn't turn on the shaft assuming you are in high range much more than low range, this is the bushing that wears out. I have my theory why this happens, other may have different opinions.
I think the bushing gets effectively flogged out by the constant load and no load condition as we drive with throttle on and off.
The gear that spins all the time we are driving in high range doesn't show near as much wear on either the shaft or the bushing.
The bushing is easy to replace when the TC is apart and the cost is small I paid $27.00 from SOR and the Canadian Toyota price was $46.00. CDan price ?
You need a bushing driver to remove the bushing without possible damage to the gear. You can do it with a capp chisel, however with the right sized bushing drive it can be used to removed and installed with same tool.
The dimension of the bushing driver are

Top rim 1.725" dia x 0.250" long

Bushing driver barrel 1.570" dia x 1.25'' long.

Fits inside the bushing and doesn't bind when installing the new bushing, this is important. Too tight and it could damage the bushing wear surface.
The centre hole on most driver handle is 5/8" so that's what I used.
The trusty 4lb engineers hammer make short work of removing and installing the bushing. The bushing can be installed backwards so make sure you line-up the oil hole in the gear with the hole in the bushing.
After the bushing is installed I checked the fit on the output shaft and it rotated very firmly "Fit's nice and tight"

This should go along way to help quiet down the whine from the TC. I don't think you can get rid of it entirely, this part of owning a TLC, but this will certainly help.

Thanks jb

[Poser]

Do you have a picture of your transfer case main shaft where the high and low speed gears ride?


Do you have any other pictures of the "bad" bushing?

[kiwidog]

Installed bushing/gear mounted on the output shaft.

Worn bushing

Trusted tool.

Thanks jb

[kiwidog]

I mic'd the shaft and it is well within spec. The oil groove in the bushing leaves a part of the shaft untouched so I used that as a reference, the wear surface had almost no wear, may 2 or 3 tenths of a thou.

Thanks jb

[Coolerman]

Excellent documentation on this. When I rebuilt my case I did not replace this bushing as I saw no reference to others replacing it as part of a normal rebuild. Hope that does not come back to haunt me later.

Please post back later and let us know if it reduced the noise level on your t-case.