Hi all i do believe that i am having a issue on my 2002 silverado 1500 ext. I hear a wierd sound ( almost humming) when i am on the gas but not when i am just coasting. However when i am driving and turn the steering the (humming sound) stops but when the wheel is straigth it starts again. i think it has something to do with the 4x4. Please help.

 

This could be your power steering pump, or it could be a thrust washer that was preloaded wrong and is placing pressure on the half shaft bearings at the side of the front diff. or it could just be a bearing going plain and simple. Only way to find out is get it up in the air and find out if the CV dust covers have been compromised, if so you have a CV joint issue at the very least. If the axle moves in and out more than a fraction of an inch, you have something going on in the front diff. A sign the bearing is failing, will be differential lube leaking around the CV boots at the differential.[8D]