Noisey American Axle

[rtbctd]

My 2wd 11 1/2 AA makes a hum or whine on decelaration,it's also louder when I turn the wheel slightly left. I had been blaming it on snow tires. How should I diagnose this

 

[JBallou]

Try different tires.

 

[AEdelheit]

hmm, well if its affected by turning I would suspect somthing in the limited slip, I would pull the cover look for metal or other contamination in the fluid and visually inspect everything. Are you positive its the axle or just assuming?

 

[rtbctd]

I'm just assuming , The front wheel bearings are new. because I was blaming the tires I ignored the noise for about 1000 miles

 

[rscurtis]

That was a common problem on early third generation trucks. Mine still does it to some extent. I reduced it by increasing the preload on the pinion bearings and bringing it close to factory specs. It could also be a loose rear wheel bearing, might check that first as it's easier.

 

[Bob4x4]

noise on decel will not be tire



GEAR NOISE

Axle gear noise can be caused by insufficient lubricant, incorrect backlash, incorrect pinion depth, tooth contact, worn/damaged gears, or the carrier housing not having the proper offset and squareness.



Gear noise usually happens at a specific speed range. The noise can also occur during a specific type of driving condition. These conditions are acceleration, deceleration, coast, or constant load.



When road testing, first warm-up the axle fluid by driving the vehicle at least 5 miles and then accelerate the vehicle to the speed range where the noise is the greatest. Shift out-of-gear and coast through the peak-noise range. If the noise stops or changes greatly check for:



Insufficient lubricant.

Incorrect ring gear backlash.

Gear damage.

 

[rtbctd]

Thanks for the information, I will road test again this afternoon

 

[HHhuntitall]

... . also check u-joints.

 

[rtbctd]

Road Tested Sunday with an extra set of ears . Noise is slighty louder on left turn. jacked up and listened with stethascope, all bearings sounded normal [no load on wheels] removed driveshaft all ujoints free,center bearing smooth. I'll put in ujoints and center bearing anyway . Where do you buy center bearing? I'll remove wheel bearings next



Thanks

 

[Prairie Dog]

Road Tested Sunday with an extra set of ears . Noise is slighty louder on left turn. jacked up and listened with stethascope, all bearings sounded normal [no load on wheels] removed driveshaft all ujoints free,center bearing smooth. I'll put in ujoints and center bearing anyway . Where do you buy center bearing? I'll remove wheel bearings next

Thanks

Regarding the center bearing, it's not only that it's smooth, it's that the rubber gets weak and sags allowing the geometry to get off ~ and I can assure you the rubber has sagged by now. But I don't think that's causing the noise you hear. .
When you turn a corner the spider gears in the diff spin at different speeds from one another. I fear this may be where your problem lies.

 

[HHhuntitall]

Are you sure it's not coming from the front? Or under the driver seat? I've seen several trucks, including some of my own, that the U-joints have gone out(or the center alignment pin) in the H unit on the front drivesaft. It can make a roaring noise, much like a bad bearing. I typically don't see many problems in the rears unless they've been run low on oil or never serviced... ... There is the possibility that the center carrier spider gear pin could be loose or falling out. I've never seen that in an AAM in a Dodge, but once in a Chevy, and several times in the older Dana's in Ford and Dodge.

 

[rtbctd]

I replaced Ujoints,carrier bearing and four rear wheel bearings. Changed rear axle fluid and road tested with noise still present. I used a car tire balancer to spin front wheels[not enough power even with caliper pistons retracted] left did spin slower. With rotor removed I could feel roughness in bearing. Hub bearing was less than a year old. I replaced with a warrantied part and noise is gone. Thanks for your responces

 

[HHhuntitall]

Glad to hear you found it. Not the first bearing off the shelf that was bad.

 

[Prairie Dog]

Thanks for updating us.