Diff Regarding a rusted out amc 20 axle assembly

[RatrodScott]

Hey yall! Bought a 83 CJ7 . It has an AMC20 rear axle assembly. The guy i bought from was putting in 1 piece axles.unfortunately for him and now I, he broke off flush with the case 4 differential cover bolts. Then proceeded to leave the cover off for a few years resulting in the rust situation you can see in the pics. It does still roĺl. Now I have some questions.

1. Has anyone had any luck removing those bolts with good success that can share their process

2. Can I easily replace the diff/gears/bearings without removing the entire axle from jeep. Ive replaced the chunk on a Ford 9" before easily. But never a AMC 20

3. If not feasible for questions 1 or 2 any reccomendation where to source a complete rear axle either new or rebuilt?

I want to stay stock but if cheaper to upgrade then so be it.

 

[CJ]

Holy rusted housing Batman!
But, good news. You should be able to get those four little cover bolts out by drilling s small hole in them to allow them to release outside tension on the threads. Then apply mucho penetrating oil, then extract. If that doesn't work you can always drill and tap for the next largest bolt and just enlarge the four holes in the cover.
There is no chunk assembly on an AMC20 . You will need to setup the backlash and pattern (pinion depth) just like any diff. It can be done under the Jeep but judging by the rust seen it would be best to pull the diff for access and cleaning. It's really easy to pull, remove four U bolts and one rubber brake line and your done.

 

[RatrodScott]

Thank you for the response. how complicated is it to set backlash and pattern. Never done it before but willing to learn

 

[CJ]

It's actually pretty complicated and needs special tools such as inch pound and foot pound torque wrench, mag base dial indicator, micrometer, marking compound and more. That doesn't mean you can't learn.
Search (Link)-> Google Search -<
Here is a video among many that explain.

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[CJ]

In addition, very few DIY people attempt diff rebuilding. An improperly setup diff usually results in major gear whine and at the extreme, failure. They usually take it to a shop.
Don't let that discourage you though as it is not crazy complicated, just time consuming without experience.

 

[Jeep Soup]

Plan B.....
Go on a Parts Safari at your local Junk Yards. Get the Axle Ratio off the VIN tag to match.
A whole rear Axle Assembly might be cheaper as you will Already have removed the Old Axle.
As said, 8 Spring Nuts, and a Brake Line.
I would recommend replacing the Axle/Spring U-Bolts and the Brake Flex Line while you are at it.

 

[Manic Mechanic]

Plan b use a ton of penetration oil soak and clean everything since it rolls. Then run it for a bit and change the oil a few times. Repeat eventually it will look new again