my name is beth and i drive a 2004 chevy silverado 2500hd 4x4. my truck has a unusual humming coming from under the front end, i checked the front differential fluids (as suggested by my dad), it was dry. i put a bottle of gear oil in it but the humming is still there. do i need to put more in, or is it something else?

 

You probably need to add more. You need it full and that will be when it just starts to drip out of the hole where the fill plug is. If it was dry, you may have some roasted bearings in there. Get some Lucas differential treatment at your local parts store. It can help.

 

Ok will do thanx.

 

I'd suggest look at the tires. Alignment, inflation ect.