11.5 Inch Ring Gear 14 Bolt Rear Trouble

[scottdarling]

Hello all i have a 2003 2500hd crew cab with a 8.1 litre with the 11.5 inch ring gear rear axle with the factory locker.My problem is when i drive my truck dow the road after it has sat over night i hear a humming noise which goes away after a mile or so. Also while im driving the ride feels a little rough as in bumpy im not sure if there is any connection to the 2. While im driving it kinda feels like there is play in the drive train theres a jerking sensation foward and back. I checked the drive shaft u joints and they are fine i disconnestec the rear drive shaft from the rear axle.I checked for play in the transfercase i can move the yoke back and forth then i checked the yoke on the rear axle i to can also move it back and forth before the tires move.Now heres the werid thing i jacked up the truck and put it on jack stands in the back after i reconected everything one tire spun then every 3 seconds or so the other would spin then stop then start then stop over and over again is that normal because of the locker.At 10mph on the speedo both tires spin.When i turn the axle yoke by hand only 1 tire will spin whats up. If anyone could help it would be great im at my wits end i just bought the truck 6 months ago from gm and i refuse to bring it to them to get repaired. The truck has 53k miles i changed the gm fluid to amsoil severe gear not to long after i bought it i dont remember if it acted different then i dont drive it much.I have also read and been told by gm that no additive is needed.Im sorry if i didnt explain it good enough im only 19

[scottdarling]

forgot to say its a crew cab

[spartus]

It sounds to me like it's acting normal. The locker in these rear ends is a EATON, which works on a centrifigal type spring lever. When one tire spins at a certain rate faster than the other, the lever will flip, and lock in the other wheel.. There will also be a certain amount of backlash in the ring & pinion when turning the pinion flange by hand. I'm sure GM has some specs on what it should be. At AAM though, where they are assembled, they are pretty tight when you turn them back and forth. They are ran on a test stand, and lash is tested on each axle before it leaves the assembly line.

[scottdarling]

so do you think that rocking feeling is normal.This is the first crew cab i have owned do crew cabs bounce more/ rode a little rougher from the longer wheel base.