Help diagnose transfer case noise
 

So I just completed a swap to a Rubicon transfer case. Everything bolted up great and checked the torque on everything, put 2 quarts of ATF+4 in. 4hi and 4low work great, the case shifts great. 2wd sounds sick. The noise sort of sounds like worn bearings maybe (it doesn't click or tick, just a constant whirring). If I apply slight pressure to the shifter forward or back, the noise gets worse. Any idea what it could be??