Rear axle nut size dana S110 (hd2)

[Braveheart]

Cannot believe that no one has asked this before...should be very helpful to the community. Dana says the MD hubs are OE specific for the S110. GM manual kindly lists all of the available 8points in the MD service kit from 3" ish to 3 7/8", so no help there.

I'd like to replace my rear hub seal on my c4500 (failed at 10,000 miles ...so much for this being a good design), but don't want to tear it down and then realize that I don't have the tool. I have a rear disc and caliper sliders if that's important.

Anyone know the size of the rear axle hub lock nut?

[Braveheart]

Surely someone on this forum can answer this little mystery. I have a feeling that this is not a rare repair if mine failed at low miles. This could be an Internet-traffic gold mine if no one has answered this before.

[DmaxMaverick]

It's a holiday weekend. Give the folks a little time and I'm sure someone will have your answer. Unfortunately, I don't.

[DieselDavy]

I was hoping Mark Rinker might chime in here. He probably knows or knows someone who knows!

[Braveheart]

Although this wasn't a million dollar question, I figured it was worth $50 after a few days of silence. So, I purchased a nut at the GM dealer to examine it. The answer is :

3.25" , 8 point nut for the C4500-5500 Dana S110 rear axle with discs. That is the "909" socket for OTC or Kent-Moore tools.

Dana tech support is completely mystified by this setup, as all of their docs show an adjustment nut and a separate locking nut. See photo. I spent an hour on the phone with their techs, and they said that it was similar to a setup that Ford used in the 90's. GM invented this racheting three piece nut (all connected), which keys on the woodruff slot. This is going to be impossible to torque correctly according to Dana's adjustment policies. The torque will build and fall as you rotate the nut through the detents. GM service manual says "reinstall nut" or something to that effect. Thanks to GM for the detailed help:( No one seems to know the adjustment rules for this single locking nut, so I figure that I'll wing it and measure the lateral end play according to Dana specs.

I am willing to bet that my seal failed at 10k miles because this bastard design was incorrectly adjusted at the factory; may even explain the vibration at 45mph. Image of what Dana thinks it should be below and GM's design underneath. (GM's solitary nut is #10) If you know the adjustment rules for GM's ratcheting nut, please chime in.

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[DieselDavy]

Brave,
Could you just assemble using Dana's nut assembly?
Now I can see why no one here chimed in!!
Good luck and keep us informed as to how it went.