Lock Hubs then a Howling noise

97 single cab 4x4 auto 2.7L

I lock the hubs and not engaged in 4x4 and i hear howling.....same thing when I engage 4x4


When I unlock hubs goes away

 

Bump

 

Truck runs good on the trail tho, been told this is normal......

 

I haven't noticed a howling noise with my hubs locked.

Does it change with speed?

 

Its not annoying or loud loud just comstant while moving, truck runs good, habent broke anything, you guessing u joints, cv axle or hubs?

 

My best fuess would be a bearing somewhere that doesn't turn with the hubs unlocked. I haven't dug into the front end much though, so I'm afraid I'm not much help.

 

Rather strange thing