For years mine has made a whining noise when cold and ambient temps are below about 50 degrees F. Became noticeable when I swapped out the stock t-case cable for the Advance Adapters unit, which mounts metal on metal to the side of the trans. We determined it most likely to be the internal oil cooler bypass, as once it warmed up the noise was gone. Never gets worse, never changes.
'09 JKRU. 4" Teraflex long arm, Teraflex R44 housing, Teraflex / Fox Resis, Poly Performance skids, Nemesis Billy Rockers, Nemesis flares, 37" ATZ P3s on 17" 5x5.5" Trailready HDs, Spyntec hubs, Teraflex BBK, Mopar BBK master/booster, Superior front & Alloy USA rear axle shafts, CTMs, Reids, Synergy drag link & tie rod, WTOR hydro-boosted steering, 5.38s, TF Dual Rate front bar, TF bumpers, Warn Powerplant, Tom Woods shafts, AA xfer case cable, Kilby canister relo, RH4x4 cage.