Chevrolet 1500 grinding noise, light acceleration

[deemon]

My 1991 Chevrolet 1500 started making a grinding/high-pitched humming noise today. I've noticed that the noise is coming from somewhere underneath the bed. The grinding noise starts when I try to maintain a speed,accelerate lightly, or deccelerate, and is almost constant after 45mph. The humming noise gets extremely loud upon accelerating after a stop. Can you please help me?

[777stickman]

Welcome to AF. Is this truck a 2wd or 4wd? Need to get the u-joints checked. Also need to check rear axle fluids.

[Ol'Jim]

Originally Posted by 777stickman

Welcome to AF. Is this truck a 2wd or 4wd? Need to get the u-joints checked. Also need to check rear axle fluids.

Yep, lube the u-joints, check differential oil level, and if it has a Carrier Bearing, (Large bearing mounted in a frame that is bolted up to the underside of the truck, supporting the mid-section of the driveshaft), I would almost bet that is the culprit, if it's not the rear end. Not too expensive, you need to unbolt the rear yoke, then the carrier brg, and drop the shaft from the trans. You'll probably need to have a driveline shop or machine shop pull the old carrier and press the new one on.