Differential - Broken Tooth

[woyster_00z71]

2007 Chevrolet Avalanche, 2WD, 168,000 miles, 8.5" 10-bolt

 

Changed the oil in my differential this morning and found a large piece of metal stuck to the fill plug magnet.  Upon inspection it appears that a tooth is missing a chunk of metal on one of the internal gears (pinion or spider?) inside the differential carrier.  We haven't noticed any issues while driving, so I was surprised to find this.  I know the below pictures don't show a whole lot, but is this something I should get checked out further and possibly replaced?  Will it hurt anything to keep driving?  First picture shows the tooth with the missing chunk.  Second picture is a normal tooth.  Last two pictures are of the chunk of metal removed.

 

Thanks in advance!

 

 

[muddkatt]

I can see metal shavings on everything when I blow the pictures up. I also see scoring on several pieces where the metal fragment has made contact when it was bouncing around. I would have a good mechanic take it apart and change any damaged parts, replace the bearings and seals and of course clean the entire thing spotless.  My guess is if you don't have it done, in a few thousand miles the metal shavings are going to force you have it done with more damage than it has now.

[davester]

might be cheaper/faster to just throw in a used rear axle from a junkyard truck

[muddkatt]

^^^  possibly, depending on what all got ground up in side.

[davester]

I'd assume you'd want at least a new ring&pinion, and on rockauto, they are about $400 (summit racing has a bunch at less than 1/2 that), probably cheaper for non-ACDelco parts, and then you've got a bunch of labor to remove, inspect, and install the new bits and setup the diff gears correctly.  And there are various other bits you replace when doing it, like seals, various crush washers, spacers,etc...  It'll be "better" in that you have new bits inside, assuming it's installed right, but it's going to be more expensive to do.  Removing/installing the whole axle is going to take less time and also be harder to screw up, but with some risk that there's something wrong with it.

 

The OP's axle should be readily available with the right gear ratio, so it probably isn't that expensive or hard to find.

 

For something like my truck ('04 Sierra Cab&Chassis DRW), the axle is likely available here in the city, but it'll only be at a used-part place, and much more expensive than those at a junkyard, as it's much rarer (10.5" axle that's narrower than the axles used in either SRW or DRW pickups).

Edited September 22, 2019 by davester