Any Axle Guru’s out there?

2007, Base H3, 152K

I am in the middle of rebuilding the front axle (the “beloved” AAM-7 7.6 IFS) due to the entire thing being overall pretty worn out. Some metal shavings in the oil, a little bit of play in the pinion yoke (not backlash, actual up/down play from the bearing failing) and also a bit of noise at 30-45 mph.

I have disassembled the carrier down to its bare bones. The only thing I have left is to remove these incredibly stubborn bearing races inside the carrier.

I considered re-using them, except that there is a ton of pitting on them….like a lot. Definitely not reusable.

I am not a welder, so I can’t use any welding techniques to get them out, but things I have tried so far:

1) punching them out - no amount of hammering, etc. has even gotten them to budge. Not even a millimeter. Lots of penetrating oil was applied, including letting it sit overnight.

2) putting the entire carrier in the oven for 30 minutes at 300F (being a 2007, it’s an aluminum housing, otherwise I would have went higher on the temperature). After taking it out of the oven, I immediately tried hammering it out with a punch. Still nothing.

3) putting the dang thing under a hydraulic press and trying to press them out. I didn’t apply a ton of pressure in fear of cracking the aluminum housing, but there was absolutely no signs of them wanting to come loose. I left one of them under tension for about 30 minutes hoping I could go inside, have a cup of coffee and hear a loud “PING” if they finally came loose. Didn’t happen.

4) last resort, I took the Dremel and started cutting one of them out.

Now here is where I’m a bit stumped;

I have made several cuts that are easily cut through the entire race, and it is very clear I am down to the bare aluminum differential. My hope is I could start cutting out little pieces here and there and when enough of the pieces are gone, the thing will fall out.

But even when I have cut out an entire piece of race down to the bare differential, it refuses to fall out. Even after chiseling/etc. It’s like the entire bearing race somehow fused itself to the aluminum casing.

Which got me thinking: is there some type of cement/special adhesive that GM used when assembling these axles? And if so, how do you break it free?

I’ve read there are products out there (such as Loctite 660) that are specifically designed to tighten up loose bearing races; but in order to break them free, you need temperatures upwards of 500F. I would think a temperature that high would damage the aluminum housing for this axle.

Basically, is there any other methods to removing these races? Or am I ****** and will need a new housing?

My next task will be to take it to a machine/welding shop to see if they can have some fun with it.

On that note, if anyone has a spare 7.6” carrier housing only (with the races ALREADY removed) laying around, you have a buyer.

 

Spoke too soon, I managed to get them loose.

First one I had to cut out completely. Second one I had to weaken it by cutting through it, then re-attacked it with the hydraulic press.

Now I can finally get to making a good paint pattern and shim everything.

Lesson learned; never give up!

 

Great work (and this I can say as I have been there on a Tahoe I did the same job on) When I put mine back together I did not use any special adhesives per the GM manual.
Anyway, it sounds like your well on your way! Keep the faith buddy and Merry Christmas to you, hope your back on the road soon!

 

Just finished rebuilding the axle today. So far, life is good!

I used a MOTIVE GEAR Ring and Pinion as well as their bearing rebuild kit and overall they all worked very well. The kit did not include any thin (0.001" or 0.002") shims, so I would recommend ordering some of these ahead of time because unless you get very lucky and the 0.006" shims just happen to work out the way you want (in terms of backlash, paint pattern, etc.), you'll need the thinner shims.

I ended up using 85W-140 GL-5 gear oil instead of the recommended 75W-90 GL-5 oil. I figured with all the weight of the H3 riding on such a small axle, a little bit of extra protection might not be a bad idea; time will tell on whether or not the thicker oil helps protect things better, or if it will cause the differential to wear out quicker due to the thicker oil not providing adequate flow to the bearings.

Not sure if its because of the new bearings, the MOTIVE Gears, or the thicker oil, but the differential is extremely quiet. Almost zero noise, whatsoever. Only a very, very small amount of howling at 60+ mph, but I'm honestly not convinced it isn't coming from my AT tires, vice the differential itself.

If anyone has any questions about rebuilding this differential, DM me and I can provide a lot more information!

Hope all is well with everyone, and that everyone had a Merry Christmas and a Happy New Year!