97 sierra makes whining noise at 40mph +

[mybad_z71]

i bought this 97 4x4 z71 sierra yesterday, driving it home it was whining and i thought it was the mud terrain tires humming, this afternoon i jacked up rear end and the whining noise was still there, it only happens at 40 mph or higher and continues until i drop below 40mph. could this be the tranny or t-case?

[Hired Goon]

Originally Posted by mybad_z71

i bought this 97 4x4 z71 sierra yesterday, driving it home it was whining and i thought it was the mud terrain tires humming, this afternoon i jacked up rear end and the whining noise was still there, it only happens at 40 mph or higher and continues until i drop below 40mph. could this be the tranny or t-case?

If you can add a sound clip to your post so people could hear the whining
It may be just a wheel bearing

[mybad_z71]

hey guys, turns out it was the pinion bearings, BOTH of them. i totally rebuilt the entire rear end including brakes and hardware, drives like a dream.