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Hey folks, thought you might be interested in a short writeup and a few pictures of the rebuild on my rear axle. It's in my 2005 GMC service truck with 320,000 miles. The pinion seal had been leaking for quite a while, last winter I replaced the seal as well as the hub bearings and outer seals as one side was leaking and the bearings were starting to feel slightly sloppy. When doing the pinion seal noticed a little play in the pinion bearings. However at that time I chose to just throw a seal at it and see if it held.

Made it a few months and a couple thousand more miles, but then it started leaking for real, and finally a couple weeks ago I crawled under there and found out I could jiggle the driveshaft up and down significantly where it attaches to the yoke. Parked it and switched over to driving my Cummins. Ordered the parts to rebuild it, new bearings, seals, new ring and pinion gear set, and a new Track Rite limited slip originally designed for Dodge applications. All factory AAM parts. As I discovered when ordering parts the factory AAM parts were significantly cheaper than others such as Yukon. Even the limited slip assembly was about $300 cheaper than had I gone with a Detroit.

Wasn't sure what bearings the kit would come with as it didn't say on the AAM parts breakdown, but was pleasantly surprised that the pinion bearings were Timken and the carrier bearings were Kobe (or maybe it was Koyo). Only reason for replacing the ring and pinion is that I assumed they would have significant wear due to the sloppy pinion bearings, also chose to replace the limited slip assembly as I figured at the mileage it would be worth it just do it all at once. Also wanted to have all the parts I could possibly need on hand before starting the tear down so as not to be stuck waiting a week or so if I found other wear internally.

Interestingly enough the ring and pinion gears looked decent still. There was some slop in the spider gears, but I wasn't sure how much was acceptable there, and wasn't about to tear into the original locker and see how that looked. The GM style locker looks rather complicated. The Dodge style appears to be relatively simple. Anyways, spent a lot of time cleaning things before and during the teardown and assembly.

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Ended up buying a second floor jack to give me a helping hand, have been wanting a second one around the shop for a while so it was a good time to just do it.

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Having a compact tractor with a front end loader is rather handy for this. Picked it right up off the floor jacks and pulled it outside to hit with hot water through the pressure washer to clean the years of crud off of it. Can't fit the forklift in the shop, so this works just as well.

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Set it up on the welding table and strapped it down good and tight. If I had a lift in the shop I probably would have just rebuilt it in the truck. But having it out on the table like this sure made it easy to work on.

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Scotch brite disks on the pneumatic die grinder makes quick work of the old RTV and gasket material left on the housing and cover. Spent a lot of time cleaning the housing. Probably went through 6-7 cans of brake cleaner during the entire process.

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Crush sleeve sure puts up a fight on these things. Tried a few different methods, but finally ended up with the 36" pipe wrench on the yoke and cranking down with my favorite 3/4" drive ratchet.

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Ended up with 45 in-lbs of rotational torque on the pinion assembly. Somewhere I read these things were supposed to be set between 25 and 50 in-lbs. Later on I found specifications posted by AAM stating 20-30 in-lbs. I think it will be okay being a little tight, but that is slightly concerning.

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Had to get creative to get the ring gear bolts up to 175 lb-ft.
 

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1077136

Set backlash to 0.003"

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Drive side

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Coast side

I've never rebuild a differential before. Reused the pinion shim off of the old pinion. Gear contact pattern looks good to me, but I could be wrong. So far so good, on driving it. Running synthetic 75w-90 in there currently. Figure will change it out after about 5,000 miles or so. Jacked it up again after driving it and everything still felt good turning things by hand. Time will tell on that one.

Overall not a difficult process, just time consuming keeping a clean work environment and double checking everything. Would likely not be worth doing for someone that doesn't have the tool selection already in place. Couldn't find much online about rebuilding these things, so thought that it might be helpful to some if I posted this.
 

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Very nice writeup. Your friends will be happy to find out that you can do differential rebuilds!
 

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Great write up! I haven't torn down a rear diff, or any diff for that matter. If the time comes, reading through your post gives some confidence if and or when the time comes.
 
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