A month of so ago our '03 Durango with a 9.25 rear end started making noise.
I recently decided to rip it apart in hopes of finding what was causing the noises.
In the attached video you can hear it makes grinding/rubbing sounds at low speeds, and at higher speeds makes a high pitch humming sound (no humming video) that goes away when coasting.

I expected to find sloppy gears and bad bearings. However, the bearings appear to be in good shape still. I pulled the axle shafts and cannot see any wear or feel play or grinding in axle shaft bearings. I cannot really see the carrier bearings very well with it in the truck but cannot move the carrier in any direction as they also seem to be in good shape.
I cannot move the pinion either as it seems to be in good shape.
The U-Joints are tight, the noise does not care which wheel is spinning or if the truck is turning. The rear brakes are brand new and installed correctly, the splines on the axles look good, the fluid was full during the video, etc;
I've checked as much as I know how and the only thing I can find is that the gears have some play.
I have no way of measuring precisely how much play they have, nor do I really know how much play is acceptable. But just using my general knowledge it seems excessive to me. I've attached a video of the play in gears. I notice the most play in the spider gears that the cross pin goes through.

I'm assuming the gears are just plain worn out which would explain the humming sound, but what about the low speed grinding? Would the gears cause this..? I wouldn't think they could but let me know if I'm wrong. Or let me know if there are any other ideas about what may be causing the grinding noise.

Also has anybody rebuilt a rear end in their garage before? I know it has be very precise to last, I'm not even going to try it if there's a good chance I'll biff it anyways. And this vehicle is not worth paying somebody to do it. I'd rather we run it till it blows than pay somebody.

Thanks!

Update - apparently I have to try and find an acceptable video format to post it here but it's coming!


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I had a similar issue with a Furd F150 recently at work. same basic design rear end. same thing// an obvious bearing noise that wasn't evident as to where it was coming from. I pulled the cover, pulled the axles, and pulled the carrier. It wasn't til I pulled the carrier til I found the problem. One of the carrier bearings was all pitted and chewed up. the pinion seems to spin free, no slop, pinion seal not leaking. so I ordered new carrier bearings from the local NAPA today, will have tomorrow. and that's tomorrow's job to press them back on and reassemble. the gears on this rear end look like new and I would venture to guess yours might well, too.
does your noise get better/worse under power and do the opposite when you let off the gas and coast? If not it probably aint the gears.

 

If all you are doing is replacing bearings and not replacing ring, pinion and/or carrier at this point, you can most likely get by with keeping track of shims and putting same shims back on in same location.
done it more than once. and yes I have done it here in my home garage before. but for tightening the pinion nut especially and setting the crush sleeve it helps tremendously that I have my own 2 post lift to get it up high enough to swing and put weight into the breaker bar/ torque wrench. If you don't have to mess with the pinion shaft/ bearings then its a little more doable off a set of jack stands. but you cant see them/ inspect them without removing them

where is this percieved play you mention? I have heard that later model 9-1/4s have had a tendency for the pinion nut to loosen which could give you this play. They all should have a LITTLE play between the ring and pinion. that is called "backlash"/ opposite would be preload and you dont want that in the gears because that means they are binding which WILL cause them to eat themselves.