AMC 20 vs. Chrysler 8.25 - JeepForum.com

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post #1 of 17 Old 03-21-2010, 02:33 PM Thread Starter
JeffKDX220
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AMC 20 vs. Chrysler 8.25

Im in the process of building a 81 cj7. And everyone knows how easy it is to break a AMC 20 rear end. I am thinking of switching to cherokee axles (D30 in front and Chrysler 8.25 in the rear), thats what i have in my cherokee and i have never had a problem.

And if any one as done this or as heard of anyone doing this let me know the results... and any pictures of this would be greatly appreciated!

Thanks, Jeff

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post #2 of 17 Old 03-21-2010, 02:53 PM
crcj7
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i dont think there the same side drop . the amc 20 can be very strong with one peice shafts and a truss the tubes are the weak point along with the shafts the ring gear is large and strong

geter done goter did flipeder over didit agian
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post #3 of 17 Old 03-21-2010, 03:01 PM Thread Starter
JeffKDX220
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what do u mean by side drop?
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post #4 of 17 Old 03-21-2010, 03:20 PM
crcj7
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I think that the xj is a passenger drop and the cj is a driver side drop . dont quote me .

geter done goter did flipeder over didit agian
i need an nv3550 any one need a hardtop
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post #5 of 17 Old 03-21-2010, 04:15 PM
kickingprop
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Quote:
Originally Posted by crcj7 View Post
I think that the xj is a passenger drop and the cj is a driver side drop . dont quote me .
vice versa... CJ front axles are passenger side drop and XJ's are Driver side...

there are lots of other stronger options with better aftermarket support than the 8.25... But the AMC20 with good one piece shafts should be plenty strong.

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post #6 of 17 Old 03-22-2010, 04:10 PM
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Quote:
Originally Posted by JeffKDX220 View Post
Im in the process of building a 81 cj7. And everyone knows how easy it is to break a AMC 20 rear end. I am thinking of switching to cherokee axles (D30 in front and Chrysler 8.25 in the rear), thats what i have in my cherokee and i have never had a problem.

And if any one as done this or as heard of anyone doing this let me know the results... and any pictures of this would be greatly appreciated!

Thanks, Jeff
  1. Wrong drop.
  2. Unit bearing axle. Unit bearings are non-serviceable, expensive to replace, and you will lose your lockouts.
  3. Wrong bolt pattern (you'll need new wheels).
  4. Is the 8.25 the later 29-spline? Don't bother is it isn't.
  5. Is the XJ D30 at least a non-disco HP model? Don't bother if it isn't.

This is how NAXJA Midwest Chapter elected officials like to treat their resident users and former multi-year supporters.


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post #7 of 17 Old 03-22-2010, 04:52 PM
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Quote:
Originally Posted by kickingprop View Post
vice versa... CJ front axles are passenger side drop and XJ's are Driver side...

there are lots of other stronger options with better aftermarket support than the 8.25... But the AMC20 with good one piece shafts should be plenty strong.
oops . i sliped on that but you get the idea .

geter done goter did flipeder over didit agian
i need an nv3550 any one need a hardtop
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post #8 of 17 Old 03-22-2010, 04:53 PM
BriansCJ
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If your going to go through the trouble, go with something bigger.

The stock 20 and 30 should be fine up to 35s with some upgrades.

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post #9 of 17 Old 03-22-2010, 05:01 PM
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I can think of dumber swaps. Like IFS. Or a golf cart axle. But that's about it.

How many broken AMC 20's have you personally seen? Compared to the internet myth that the 20 is the most fragile thing since a Faberge egg. Plenty of AMC20's have held up to more than 35 years of abuse and are still going strong. The Hummer H1 uses AMC20 centers and it weighs as much as a house.
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post #10 of 17 Old 03-22-2010, 05:08 PM
crcj7
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ahaha thats cool about the h1s .burn . but truss 1peice cromo up front and go .

geter done goter did flipeder over didit agian
i need an nv3550 any one need a hardtop
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post #11 of 17 Old 03-22-2010, 07:42 PM Thread Starter
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Quote:
Originally Posted by Pathkiller View Post
I can think of dumber swaps. Like IFS. Or a golf cart axle. But that's about it.

How many broken AMC 20's have you personally seen? Compared to the internet myth that the 20 is the most fragile thing since a Faberge egg. Plenty of AMC20's have held up to more than 35 years of abuse and are still going strong. The Hummer H1 uses AMC20 centers and it weighs as much as a house.
Iv broken 3 myself
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post #12 of 17 Old 03-23-2010, 08:23 AM
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i blew my 20 all to hell, but I was roasting 33s with a 360. But still you're wasting your time, if you're going to swap go bigger

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post #13 of 17 Old 03-23-2010, 08:24 AM
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Quote:
Originally Posted by JeffKDX220 View Post
Iv broken 3 myself
You've broken 3 center sections?


I don't think anyone is contesting the 2pc shaft design strength issue.

This is how NAXJA Midwest Chapter elected officials like to treat their resident users and former multi-year supporters.


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post #14 of 17 Old 03-23-2010, 08:27 AM
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If you've broken 3 AMC 20s (probably one piece axles), you will add Chrysler 8.25's to that list if the swap is done.
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post #15 of 17 Old 03-23-2010, 10:48 AM
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The amc 20 is definitely a tought axle with 1 piece shafts. I've put mine through a lot of abuse and have only broken 1 shaft running 35s/36s. If you are questioning the strength of the amc 20 I wouldn't even consider the swap, especially with the front axle being what it is. If I were you I would go straight for a 60 or 9" rear and 44 or 60 front. You can probably get a good deal on a set that are already somewhat built.
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