Transfer Case Noise

[Beachhead]

2000 TJ Auto, 32RH

I've got a strange noise coming from what I believe is the transfer case. Sort of sounds a like a swishy underwater noise (video linked below)

Changed out transmission fluid + filter, and transfer case fluid recently to combat the noise, and it didn't make any difference. Existing level and color was good. Only odd thing was the transfer case fluid seemed a little metallic in sheen, like a metallic paint when in sunlight. Put a magnet to it and didn't catch anything so aluminum. No large chunks, just the metallic sheen in the ATF.

It sounds like it's coming right underneath the shifter, so i'm just assuming transfer case. It only makes the noise when the Jeep is in motion. Revving at a stand still, even while in D or R the noise is not present.

Are they just normally noisy like this, or is there something wrong?

Thanks

Video:

 

[IOwnCalculus]

I never thought to describe it as "swishy underwater" but going back and watching my own video versus yours, I think they sound about the same. In this video I had the case in neutral and the transmission in gear.



This is what I ended up draining out of that case.

I rebuilt the case with a new planetary, new bearings, new chain, and new pump. Root cause was the last person who was in this case (not me!), when installing the SYE, had used way too much RTV - so the case was slowly starved of oil even though it was full.

 

[Beachhead]

I never thought to describe it as "swishy underwater" but going back and watching my own video versus yours, I think they sound about the same. In this video I had the case in neutral and the transmission in gear.



This is what I ended up draining out of that case.

View attachment 374915

I rebuilt the case with a new planetary, new bearings, new chain, and new pump. Root cause was the last person who was in this case (not me!), when installing the SYE, had used way too much RTV - so the case was slowly starved of oil even though it was full.

View attachment 374916

As far as i'm aware I don't have a SYE. Would there have been a reason why the transfer case would have been opened up? The only witness marks I saw were on the fill and drain plugs, which had previously been accessed using the wrong size allen wrench.

Your noise is also present when the vehicle is not in motion, judging by your RPMs? Mine does not occur when the Jeep is stationary.

 

[IOwnCalculus]

Yes, but I had the transfer case in neutral so that at least the input half of the transfer case was still spinning. If you're sitting still in drive with the case in any position other than neutral, nothing in the case is spinning.

If putting the case in neutral and putting the transmission in drive still results in no noise, then that reduces the possible causes to something on the output side of the transfer case, or possibly a driveshaft.

And these cases need a rebuild for plenty of other reasons too - I just happened to have a very clear root cause available for why my transfer case fluid was full of aluminum shavings.