My rearend AMC 20 clunks

[76cj7chick]

My neighbor helped me to remove the rear driveshaft but he was very forceful and I guess he doesn't know about wd40... Anyways, while trying to loosen the very rusty nuts, he held the driveshaft with a screw driver so it wouldn't move and now my jeep's rear end clunks and its very difficult to turn. Feels like its caught on something. (I kept the driveshaft off so it won't destroy my Transfer Case .) And I havent driven the jeep yet..

I will probably have it towed to a shop as I have never worked on the differentials.... Well, I've changed oil and gaskets but no rebuilding spiders and such..

Any idea what he did to the rear end? Also any idea on the cost to fix? Or should I look at used replacements for the cost to repair? What replacement rear ends would be an upgrade? May like disc brakes too.

Thanks bunches guys.

 

[jakeh937]

I'm no expert by any means but that seems strange. Why were you removing the shaft to begin with? Does it turn freely?


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[Torxhead]

I would first suggest keeping that AMC differential, I have seen some set up quite well after extensive modifications. Then find a dependable shop that can do the work for you. Any chance of finding a local Jeep club to get things going for you?

 

[gr8dain]

Does the yoke have any play in it? I am wondering if the pinion seal got messed up. Hard to diagnose from here, but seems odd. Did he use the screwdriver as a way to hold the driveshaft still by shoving it through the u-joint?

 

[76cj7chick]

Hey thanks for the responses. To answer your questions:

We removed drive shaft due to starter eating flex plate-had old broken mounts.

Yes, he shoved a long screwdriver in the ujoint to hold the driveshaft from turning while unscrewing nuts. It was free turning before he did this. Didn't want to wait for wd40. :/


I tried to giggle/move the yoke back and forth but doesn't move. May be jammed. If i rember cottectly, my front yoke has slight play. But it turns freely and no sound. But he didn't need to wrench on it as much to remove.

There are a couple of jeep clubs. I belong to a few. But thought bid ask ya all first. Thanks for the help.

 

[jakeh937]

Hey thanks for the responses. To answer your questions:



We removed drive shaft due to starter eating flex plate-had old broken mounts.



Yes, he shoved a long screwdriver in the ujoint to hold the driveshaft from turning while unscrewing nuts. It was free turning before he did this. Didn't want to wait for wd40. :/





I tried to giggle/move the yoke back and forth but doesn't move. May be jammed. If i rember cottectly, my front yoke has slight play. But it turns freely and no sound. But he didn't need to wrench on it as much to remove.



There are a couple of jeep clubs. I belong to a few. But thought bid ask ya all first. Thanks for the help.

That is strange. Is there only one particular spot that the clunk happens on? Do you still have backlash in the yoke?(you should be able to feel a few thousands backlash on the gears)


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[gr8dain]

Did you try to use the same screwdriver to apply force in the opposite direction (carefully)? To see if it would free it up the same way that it bound it up? Not necessarily a solution as even if it does free up, I would look for any issues caused.

 

[Hedgehog]

I've gotta say this, A differential is very robust, yes even an AMC20 , sing something for leverage to remove universal joint bolts shouldn't hurt either the U-joint or a differential. The worst thing that might happen would be the relatively small U-joint cap bolts might be damaged. About the only problem beyond that would be pinion shaft seal damage or U-joint damage. If he damages the U-joint it was ready to go anyways, seal damage is relatively easy to fix.

Did he remove the Yoke nut? The yoke nut sets the rear bearing preload. Mess that up and you might get a "Clunk", but all you'd need to do is torque it to spec.

 

[mriplaybass]

Check the dust shield on the back side of the yoke. It is possible that he bent it and it is hitting the differential housing when it turns. If this is the case, you should be able to take the yoke off and straighten the dust shield using an anvil and a ball peen hammer.

 

[Belizean]

Man I sure wish I still had the family anvil . That was sold by my dad along with the ranch. All I have now is a piece of 1 inch plate

 

[76cj7chick]

Thanks for the brainstorming guys.....

To answer your questions:


I tried to turn the pinion both ways and its like its hanging up. I will go out and check the dust plate did look tight against the axle. And then my brother and I put the jeep in neutral (still with driveshafts off) and pushed it back and forth and the rear clunks. (Didn't do very hard or much as afraid could do more damage).

I will check to see if he bent the dust cap.... and Hopefully that is all is the issue.

All Ujoint bolts have been removed when driveshaft was removed.

I truly hope ya all are right about that it may just be the dust cap or pinion seal. I will check it out and let ya know if I figure it out.

THANKS!

 

[Hedgehog]

The seal might be bent, but unless it is REALLY bent horribly it shouldn't cause a "Clunk".

 

[76cj7chick]

I checked the rear end again and tried moving it with a screw driver and then pop up the dust cap but it was really tight and was afraid to turn it too far cause it clunks both when turning left and turning right. I will let the shop know the issue and hopefully it is just a pinion seal....

Thanks again guys for your help and ideas.

 

[76cj7chick]

That is strange. Is there only one particular spot that the clunk happens on? Do you still have backlash in the yoke?(you should be able to feel a few thousands backlash on the gears)

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Hi Jakeh937-
Sorry, what do you mean by "backlash"?
:/ it turns both ways about an inch or so but then stops and if I try turning more it "clunks" or "clanks" like hits something metal and stops.

Sorry. This is my first time dealing with a rear end. I will have the shop check it out. Hopefully its just the seal. :/
Thanks!

 

[mriplaybass]

An inch?!! Sounds like something is amiss inside. Last year one of our group on the Colorado ride had the ring gear bolts loosen up on his Dana 30 front. Same symptoms that you describe. Play it safe. Take the differential cover off and make sure the ring gear bolts are tight. I believe 65ft.lb., but I am not positive.

 

[76cj7chick]

An inch?!! Sounds like something is amiss inside. Last year one of our group on the Colorado ride had the ring gear bolts loosen up on his Dana 30 front. Same symptoms that you describe. Play it safe. Take the differential cover off and make sure the ring gear bolts are tight. I believe 65ft.lb., but I am not positive.

Thanks Mriplaybass. The little jeep is at a shop I let them know about the issue with the rear differential. Hopefully its a simple and inexpensive fix.

 

[jakeh937]

Hi Jakeh937-

Sorry, what do you mean by "backlash"?

:/ it turns both ways about an inch or so but then stops and if I try turning more it "clunks" or "clanks" like hits something metal and stops.



Sorry. This is my first time dealing with a rear end. I will have the shop check it out. Hopefully its just the seal. :/

Thanks!

No need to be sorry! A lot of us on here come to the forum because it is our first time doing something and we all need some help. Backlash is a term to refer to the proper spacing between gear teeth. To loose and you get pre mature wear. Too tight and you get pre mature wear. I hope it's something small, simple, and inexpensive for ya! Keep us updated!!


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[76cj7chick]

An inch?!! Sounds like something is amiss inside. Last year one of our group on the Colorado ride had the ring gear bolts loosen up on his Dana 30 front. Same symptoms that you describe. Play it safe. Take the differential cover off and make sure the ring gear bolts are tight. I believe 65ft.lb., but I am not positive.

That's good to know. I will let the guys at then shop know it could be loose bolts.

 

[Lumpy Grits]

IF, you are still running the OEM 2-piece axles. Check the tightness of the axle nut on both axles.
Unless you are running a Detroit Locker. You should not have any where close to that amount of rotational play.
LG

 

[76cj7chick]

IF, you are still running the OEM 2-piece axles. Check the tightness of the axle nut on both axles.
Unless you are running a Detroit Locker. You should not have any where close to that amount of rotational play.
LG

Hey lumpy grits- I believe its still a two piece. I'll let the shop know to check it out when I stop by tomorrow.
Thanks everyone! I'll try to remember to let you know what's going on.

I had the CJ7 flatbed towed to the shop Monday. They said they got it running and just had to adjust the distributor (I had to pull it to remove the engine and Transmission from the blazer so it wouldn't get destroyed. And wasn't sure about the distributor placement). The owner reported that I did a good job. However just got a call yesterday about wiring concerns/confusion.... But I'm not surprised as this is one of the main reasons I had it towed to them. They want men to stop in tomorrow to see how its coming along. I feel sooooo much better with having a professional team check my work and correct anything wrong.

Peace! Happy Jeeping!
Thanks again for the help!