o4 2500 whinnig noise

[dcmock]

I have a 04 2500hd with 97000 miles . I am hearing a whinnig noise when when giving it gas going down the road any where from about 40 mph and up. sound like comming from the rear end but I changed the rearend oil and still get noise. When I am driving and let off the throttle the noise gos away but comes back againwhen I give throttle. Wondering if it could be the tranny

[dwill3015]

What kind of shape are your U-joints in? Also check for slop at your rear-end yoke or pinion nut. If all else fails, take it to a reptable mechanic, driveline shop, or tranny shop to have them diagnose the problem.

[collinsperformance]

i agree u-joints or rear end wine. need to tst the joints and see if they are the issue and continue thru the drivetrain...mike

[dcmock]

I jacked the truck up and checked the rear end for play and drive shaft and didnt find anything unusual , I am wondering if it could be the bearings on the out side of the axl , how common are thses to go out

[tbplus10]

The 2500 has a full floating rear axle, the bearings dont usually go out but if you loose the oil seal (which is prone to failure) it can take out the bearings. Look for signs of oil leakage around the brake backing plates.
The carrier bearing can also cause a whining noise when it's going.
A real good way to diagnose rear axle issues is to chock the front wheels, place the truck securely on jack stands under the rear axle, start the truck and run it in gear.