2000 Chevy Silverado Whine

I have a 2000 Chevy Silverado 1500 and there is a soft whine coming from the underside of the vehicle just behind the cab whenever the engine is running.



I crawled under there to locate the source of the whine, and it seems to be coming from a long rectangular “box” on the left hand side of the underside of the vehicle. Any ideas what this might be? It almost sounds like an electric motor straining to push something that it too heavy for it to move, or like a shop vac when the hose gets clogged.



I’d rather not take it into the shop if its nothing to worry about. I just don’t recall ever hearing it before today, and it’s pretty noticeable if I have the A/C and radio off and the window rolled down.

From your description, I would say it’s the transfer case (4WD, right?). Check the fluid level immediately.

It is a 4x4, with a manual-shift transfer case. Is that something I can check myself, or do I need to bring it into a shop? The user manual is pretty vague about how to check and refill it.

If I keep it in 2x4 for the time being will it be ok until I can get it into a shop?