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RAD529C Axle

Full Floater

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Im working on a single axle R with a RAD529C and a CRD1171 Carrier.   Do we like these axles?  Is there anything to look out for in regards to problems?  According to the build sheet and some info I found online, the CRD1171 is some sort of power divider.   How does that work in a single axle?



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Definitely never seen one of these 

And as for power divider that was mentioned back at the beginning 

I can see a housing that looks a bit like one there but as to how it would on a single drive ??

No idea at all

My first thoughts were a bit like LSD but I cant see how that would work f from the housing out the front 

The banjo housing looks a little like a normal top mount Mack housing turned 90 degrees 

No idea if that is the case

I assume that it is double reduction  ?



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what year is the 'R' model? I havent found a manual for that rear end yet..  Mack E-Media, didnt help..  I would love to see it up close to get a better understanding of how it works..  I wouls say itsa locking diff. over a power divider, since its a single 'x'...   jojo

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That does look to be a double-reduction axle.  You can see the caps for the cross-shaft in the lower picture he sent (see below).  I have never heard of any issues with these.  They are, as mentioned above, not that much different from the standard Mack tandem axle, just rotated 90°.

Power Divider makes no sense whatsoever in a single axle, UNLESS they put in something similar to the inter-axle Power Divider as a limited slip unit?  Instead of biasing power to the front or rear axle, it would do so to the LH or RH axle?  Just guessing on that, though.  Basically would be like a gear type limited slip unit.  Maybe somebody smarter than me can shed some light on that.

Incidentally, I have seen both these "front loaded" and "top loaded" Mack axles in single-screw applications.  I saw a LOT more of these "front loaded" units in B models than in R models.

I say keep it!  And paint the "Mack" script in a contrasting color so everybody can see it!



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"Eagles may soar, but weasels don't get sucked into jet engines."

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On 9/27/2022 at 10:36 AM, Joey Mack said:

No biggie, just tossin some stuff out there...  When I did the B-model, I removed the inner seal, and filled it with oil... 80W90... jojo

back in the day when a conversion was done changing from inner oil seal removal to one seal ,the outer seal had to be changed from leather grease seal to "new" style oil seal . today must be one style fits all ? 

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I am also posting my thoughts about the hub seal/s,   is because if you are going to use this axle, you may as well pull the hubs to inspect the bearings, and then re-seal the hub's the best way possible. grease has worked for decades, and oil bath is pretty good too..  jojo

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This axle is from a 1976 R 685ST

Yes I will be pulling the hubs to give it a good inspection and replace the hub seals for sure and likely the brake linings.  Hopefully I can get a number off the seals when I pull them out.  Will change the gear oil and probably leave the rest alone for now.

Yes I do believe that the "power divider" description in the build sheet might be reference to a LSD type axle, shifting power from side to side instead of axle to axle.   After checking oil levels I will drive the truck over some loose ground with no weight in the back and see if both wheels have a tendency to put power to the ground instead of just one wheel.

I think painting the MACK lettering on the rear of the axle in the same red that the cab is going to be, is and excellent idea.   Let everyone behind me know for sure they are following a pedigree Mack.   May as well throw some Mack "greatest name in trucks" mud flaps on to!

Edited by Full Floater
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