2003 Silverado Whineing in rearend

I have a 2003 Silverado 4x4 Ext Cab. I purchased the truck brand new in 2002. It has 65000km on it.
I have already had to replace the entire brake assembly in the rear end.
GM thought disc brakes on the back end were a great idea. But guess what, I had to replace discs and pads at 55000kms. for $500. Not happy.
Nice work GM, with the admission of bad engineering, by switching back to drums on the rear end for 2005 Silverados.

Now, my latest problem. 2 weeks ago, I noticed a whine in the rear end while driving. It has gotten progressively worse, and now as I accelerate and slow down, it screams. No leaks in rear pumpkin and it's full of oil. What could it be??? Any guesses? Seems like its coming from the driveshaft. or possibly the rear pass. side. Anybody have any Ideas???

Fergie in Ontario

While I know that many Silverado/Suburban/Tahoe/Sierra/Yukon/Escalades have trouble with the rear brakes (my sister's suburban has been to the shop more times than i can count for them), many of us, myself included, have not had any trouble out of the rear brakes (knock on wood). So, that leads me to believe that it's probably about a 50/50 mix out there as far as bad brakes and good brakes that are on these trucks

problems seem to be more aggravated operating in dirty/dusty environments.

Only the pickup trucks went back to drums. Avalanche and SUV's still have discs.

Any of you lad's have any suggestions as to what might be making the rear end whine???

Does it whine or howl under acceleration or deceleration? If so, it's the gear set in all likely hood.
Bearing noise is more constant...pinion brgs usually whine
Axle bearings usually growl.
If you got a 2 piece axle...remove the rear portion..take note on alignment as you don't want to get it out of phase phase putting it back together. Loosen bolts holding steady brg on crossmember and spin it....it should spin smooth...if not replace.
Still while its apart and you want to diagnose further...take the wheeels and brake drums/rotor&calipers off. Then spin the pinion yoke and feel for roughness. If the pinion is worn to the point of making noise it will feel rough. Also spin each axle and note for roughness.
If you want to go further take the cover plate off and check the oil. Check the backlash.....newer models run fairly tight around .005. Also check the gear pattern with some "prussian blueing". If you suspect it the gear set, my advice is to take to dealer as the new units are extremely hard to set up properly without special tools, and even then they are a bear. GM changed the design of the new gear sets requiring synthetic oil and tighter backlash than the older sets.....advantage is quieter running gears. I'm not too sure but if you are determined to do yourself I believe you can use gear sets from an older application.
Hope that helps.

change fluid in rear diff!
CHANGE FLUID IN REAR DIFF!!
whining is always sign of high RPM issues. you have only few things in the rear that will do this:
1. gears in rear diff
2. bearings.

so far, rear end whine is like 90% diff fluid low.

by the way, though i understand your gripe about disk brakes in rear, personally, i'd rather not have drums. disk brakes work better. after 120 000 MILES, i still have OEM rotors. had them turned once, but that's it. and even that was at around 80K miles.
now, their parking brake is basically non functional. that is true.

next time, fork for slotted rotors. off internet, they will cost you less, and don't really warp, unless you buy from jcwhitney.