Chasing a transfer case gremlin

[RaymondT]

I have bearing noise in the transfer case that has me stumped. I've researched some 40 hours chasing this down so any suggestions would be appreciated. I've seen threads in various forums with the exact same symptoms and no one has been able to pin it down. It's not the axles, clutch, drivelines, transmission, or transfer case shifter adjustment. All have been replaced/rebuilt/rebearing'd. When I rebuilt the transfer case, there was no visible damage to anything internal. I put in high quality chain and bearings. Everything was silent for 100 or so miles, then the noise came back.

Symptoms;

- noticable gear noise in 3rd, 4th, 5th on decel or accel. Gets louder as the oil is warmed up (ATF+4 or 10W30). The more load in the TJ, the louder it is. Like with two or more people.

- put it in 4WD, the noise almost disappears. When you go back into 2WD, the noise doesn't come back right away. Takes 3 or 4 seconds.

The noise is a spinning-shaft bearing growl. Never seems to get any worse but it's damn annoying.

 

[Rob5589]

My trans (6 spd) and/or tcase get whiny when hot. So much so a guy asked me if I had a supercharger

From reading on other sites, they are just noisy.

 

[Chayton]

My 06 6 speed has the same kind of noise..iv been searching for "something" to turn up for couple months..i haven't owned it long.
I'm running Royal purple synchro in it.

Couple of my buddies with the early jk's have same noise


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[RaymondT]

I've heard some of the 6 speeds and NV3550's were noisy. Mine is the AX5. I'm sure this is the transfer case input though.

Another weird symptom is the growl goes away at 2300rpm and above on acceleration. Shuts right off! I'm almost tempted to replace the harmonic balancer and have the flywheel/pressure plate balanced. The four banger is pretty rough around the 1500 rpm mark. All the mounts are new.