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Rear End Rebuild. - A First For me


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I’ve never rebuilt a rear end before. I want to. I have some spares and I want to put a 4.11:1 in my Chrysler.  Seems like a good winter project to me. I’ll learn as I go. I’m really just an apprentice running amuck with no Journeyman watching over me. 

I’ll post questions here as they arise. Hopefully someone can steer me right. I’ll take the carrier housing to work this week and see if I can impact that pinion flange nut off. I don’t have anything powerful enough here at home. 

I’ll think I’ll shop around for a new crown and pinion set. This one’s been around the world a few times times. By the looks of it, it might have been under an extended drain interval maintenance plan too. 




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Not sure you can find a new set BUT since most folks want 3.73 or 3.54 R & Ps you should be able to find lots of used 3.9 and 4.1 used cheap!

As always a shop manual is a very good investment.

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I have seen those same lines in NOS MoPar ring and pinion sets.

That ring gear really is not that bad.

You can see where the gears have still never worn into those factory machine marks.

But yes hunt down a better ratio...

Edited by Dodgeb4ya
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I'm looking forward to see how it turns out.  ..... The rear ends scare me with all the special tools needed to properly set them up .... maybe our old rear ends not so picky?


When I changed the rear pinion seal on a 1972 Jeep CJ5, the torque spec was around 250 ft#

I had a co worker we called animal. He jumped at the chance to do the torque.


I set the rear wheels on car ramps & parked a company service truck bumper to bumper so the jeep would not move. While Animal torqued the pinion nut.


There is also a crush sleeve inside that needs this torque ....  Then you need to use the goop to measure how the gears  fit left & right ... forward reverse .... just way outside my wheelhouse .... I know Kieth can handle this   :)


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The only really tricky part of the differential is setting the pinion depth.  Once that is done the rest can be handled with a dial indicator and some sticky grease to check the tooth engagement pattern. 


I don't recall the older units using a crush sleeve, just selective spacers to set pinion preload as well as depth.   I think my old Motors manual covers it.

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8 minutes ago, kencombs said:

I don't recall the older units using a crush sleeve, just selective spacers to set pinion preload as well as depth. 

Sounds correct ... I think some of the chebby like my 1991 is the same with spacers.

Was my Jeep with the Dana rear end that I played with .... It had a crush sleeve ..... My chebby has spacers, but it was different how it was setup.


I really am looking forward to the future videos @keithb7 will post to see how these old mopars work.


I can even share years ago I changed the "Hogs Head"  on my 1961 Dodge sweptline.  ..... Pull the axles & drop it out. Slap in a different one & install the axles ... Think it took 1 hour.

I never disassembled a Hogs Head ... just replaced them.  ....... This is not a simple job to rebuild one .... looking forward to see it.


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I was kinda thinking I’d learn what I’m doing before I publish a video about it. Lol. I am pretty green when it comes to rear ends. I understand them. I’ve certainly “read” lots about them, yet we know that means little until we put that knowledge into practical use. Book-smart is only part of it. 

Maybe I should consider a new video method. I  disassemble an entire rear end. No commentary. Just relaxing piano music.  Then I throw it all out as I have no idea how to reassemble it all. Lol. 

Just kidding. I’ll give it a go. See what I can do. 

@Dodgeb4ya I think I see more wear on the pinion teeth. I’m leaning towards a new gear set. I’ll post more pics once I get the pinion out. I could just re-bearing this one and put it all back together. Then set it up. Yet its a long ways-in, if something howls upon reassembly. 

I’m thinking about:

jack up car

remove rear wheels

remove rear drums

remove brakes

remove brake backing plates

remove axles

remove carrier assy 

Swap out and install new carrier assembly

Repeat for reassembly.

bleed brakes

Re-fill rear end oil
Re-do it all again if I get it wrong. 

Ah well, I digress. Its a hobby. It keeps me out of trouble. 

Edited by keithb7
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The rear end really is not too hard.  You just need to be patient.  Take your time.  It does not use a crush sleeve, and uses side adjusters for carrier preload and backlash.    I have had mine apart, and it was relatively simple.  Make sure to mark everything.  Be prepared for a speedi sleeve for the yoke.  One of the harder things is to find the pinion depth and pinion bearing preload shims.

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Just remember the pinion depth sets the left/right position on the ring gear tooth and the side adjusters set the tooth depth.  Also, some find it easier to get an extra set of pinon bearings, hone out the center bore for a slip fit and use those when setting up the patterns.

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+ replace  all rear seals?



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Dear Keith. I am scared to death of any rear end and my ‘36 truck needs attention and I also have a ‘38 Plymouth 4dr something sitting on my bench kinda talking to me. I also look forward to your journey in this as I want to learn and overcome a major block doing anything related to pulling out axles and doing the pumpkin. Yeah. I am All In. Thank you for being a good teacher!

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Just an FYI I believe when I switched mine to 3.73 I was able to unclip the brake lines from the housing and swing the backing plate with wheel cylinder and line out of the way without cracking into the hydraulics

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