amc20 rear issue

[tbart16]

Hello CJer's New to the forum here is my first post. I have an 85 CJ7 T-5 AMC 258 i6 / 4.2l . Bone stock around 120k on it. Late last year I was driving along when all of a sudden i lost my forward motion I intially thought i had popped out of gear but that was'nt the case. I peeked underneath no leaks no issues no bangs no pops no foul and no go from my rear axle. So Iput the jeep in 4wd and drove home with no issues or problems. I was busy all winter and am finally getting around to bust the jeep out for the summer. I did pick up a rear in a junkyard over the winter it was cheap and available. My question is before I pull the cover this weekend what could cause this and what should I expect to find in my diff. thanks Tom

BTW : great site!!!

 

[CJ]

:ww:

You most likely spun a hub. AMC20 diffs use two piece axles. Take a marking pen and draw a line from the hub across the washer and nut stopping at the center of the axle (do this for both axles). Attempt to drive it in 2wd and then check to see if the marks still line up. I'm betting they don't. If they don't you will need to replace the axle, I would recomend purchasing a good one piece axle kit.

See this thread -->> http://www.jeep-cj.com/forums/f2/amc-20-axle-question-13794/

Here is a good pic of the axle, nut and hub.

 

[tbart16]

ah ha that makes total sense should have thought of that. I'll check it out this weekend thanks

 

[tbart16]

here is the update. Removed the diff cover Saturday just to see what was going on (needed a fluid change anyway). Everything in the pumkin looks good no metal no debris. As I spin the tires nothing in the rear moves HMMMMM. So I remove the Passenger tire and dustcover and discover the cotterpin is gone and the castle nut became loose than jammed itself on the shaft wiping out all the threads on the end on the axle.
So next step is to remove the axle from what I have gathered on line it looks like I rmove some bolts on the back of the plate and use a slide hammer to pop the axle out it seems to easy what am I missing??

I am also assuming I would have to replace the seals inside the axle housing. Any help appreciated or a link to an incredible AMC20 axle removal also appreciated thanks guys

 

[johnnyreb]

if your going that far in your tear down then you might as well install on piece axles and be done with it. it'll be one less thing to worry about.

 

[gert]

I totally agree, anything you do other than trashing the 2 piece axles are a waste of money and time Morris has some chinese as well as Superior axles for ya AMC Model 20 Rear Axle for Jeep CJ5, Jeep CJ7, & CJ8 Scrambler

 

[tbart16]

yeah I was on the fence about that ,but you guys are right I am keepeing the jeep stock it won't see any off roading besides my dirt driveway,but still better safe than sorry

 

[BusaDave9]

I realize you want to keep the jeep stock but if you want to keep it running use one piece axles. You don't need to do hard core off-roading to spin the hubs on the axle shafts. Now that that has happened you have to replace the axle, can't reuse it. Since you need a new axle get a one piece.

As for removing the axle. Remove the nut, the axle flange on the end and then unbolt the brake plate. Then the axle can be removed. The one piece axle will have a hole in it to access the brake plate bolts.

 

[BusaDave9]

The axle can not be reused after it's been spun in the hub. That big nut does not keep the hub from rotating. The nut keeps the hub pressed back on the splines on the axle shaft. There is also a woodruf key in there.

The key is destroyed and the splines are damaged. You can't reuse the axle or hub.

 

[wm69]

FULL AMC 20 rebuild and setup - JeepForum.com

Good writeup on a complete AMC20 rebuild. (Axle installation directions are in there somwhere)

 

[railroadpaul]

Hi all
How can you tell if they are one piece or two piece, with out removing them...

and BTW this is a great site... thanks Paul....

 

[thiswontbetooexpensive]

Hi all
How can you tell if they are one piece or two piece, with out removing them...

and BTW this is a great site... thanks Paul....

Get the center cap off of the rear wheel/rim. If you see a castle nut, two piece axle.

 

[railroadpaul]

Thanks for the information I'm going to check that out

 

[BusaDave9]

Hi all
How can you tell if they are one piece or two piece, with out removing them...

Thiswontbetooexpensive already answered but remove your rear wheel.
This is an OEM 2 pice axle:

The factory puts a plastic cover over the big nut.
The one piece axle wont have that big nut.

There may not be a sticker in the middle.