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Discussion Starter · #1 ·
I am running an AMC20 with 35's (bought it like that) and I'm aware that this generally doesn't last long. How difficult is it to put an entirely different axle under there, like DANA 44's? If I got it from another Jeep, would that make it easier? Is there a problem with the transmission of transfer case? Just how difficult is this? Is it better to just buy a kit to strengthen the axles I have? I'm new to the world of Jeeps, so thanks for your help.
Fred

 
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Discussion Starter · #2 ·
Very common question and there has been a lot of talk regarding the AMC20. If you look back 2-3 weeks through these posts, you will find them. Regarding the AMC 20, its a good axle if you make a couple of mods. Its strength is the large ring and pinion. Its weakest point are the flanged axles but these can be replaced with 1 piece solid axles. Others say the tubes are weak. In my opinion, a couple of tack welds on the tubes should take care of the tubes turning. If your driving your jeeps so hard that you bend them, then you must be jumping hills.

I just completed a rebuild of my AMC20 by adding Superior one piece axles, 4.10 gears and an ARB. If you are running 35's I hope u have at least 4.10 or higher gears. The Dana 44 or 60 are good upgrades, but unless they already have the gears and lockers your want, you will spend as much if not more getting it in your jeep.

If you replace the axles (about $300) and your gears, you will be in good shape....unless of course you want to spend lots of money.

John......southern CA
84CJ7,3"lift,32"BFG,4.11's,ARB,Solid Axle's
 
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Discussion Starter · #3 ·
i really dont think that replacing the amc20 with a 44 is a big enough improvement to justify doing this. the only advantage a 44 has over a 20 is a slightly stronger housing. if you replace the two piece shafts and beef up the housing you will be as strong(some argue stronger) as a 44. a gm 12bolt, 9in ford, d60, corp 14bolt and a few others that are really upgrades to the 20.

dan

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I agree. The D44 is comparable to the AMC 20 with 1-piece axles. I went to a D44 because I had them, they were free to begin with, and the ratio was slightly lower (3.73 vs 4.10). The front D44 is a lot stronger than the model 30, but we're not talking about them. If you have the AMC 20 now and 3.73 or lower (higher numerically), throw in a set of 1-piece axles and have fun. If you have high gears, and can find a lower geared axle (pair), then I might switch. The 1-piece axle kit for the AMC 20 should be $200-$300.

JEEPN
'97 TJ Sport
'81 CJ-8 Scrambled!
'71 Commando SC-1
'51 CJ-3A
'47 CJ-2A
 
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Discussion Starter · #6 ·
Well it sounds like getting the one piece kit is the way to go. Is the kit difficult to install, welding required? Also, about how much would 4.10 gears cost? I don't know what's in there now, but it's probably stock. Thanks for all your help.

 
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Discussion Starter · #7 ·
no welding required for the one piece axles, but i strongly recommend have the housing straightened and trussed. amc 20 housing are thin tubed and not well attanched to the center section which makes them easy to bend.

dan

/wwwthreads_images/icons/smile.giflet it snow/wwwthreads_images/icons/smile.gif
 
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Discussion Starter · #8 ·
Superior axles from Drive Train Direct for $299...great kit, no shims needed...the only thing is you have to have the wheel bearings pressed and there is a spacer between the inner seal and bearing that you 'might' have to shave down for the correct depth.

I got the gears from 4 Wheel Wholesale...about $230 but it included a master rebuild kit....new bearings, seal, etc. This is one area that next time I will pay someone to do it. You will need a press in order to get the old pinion shaft out and the new one back in. Its a lot of work. As for your current gears, if you are running 35's and have stock 3.31 gears...yuk...I don't know how you drive it. Take the time to jack it up and spin the wheels. Count how many times both wheels go around to one rotation of the driveshaft. You don't have to be exact...its most likely 3.31 or 3.73 if stock.

John......southern CA
84CJ7,3"lift,32"BFG,4.11's,ARB,Solid Axle's
 
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Discussion Starter · #9 ·
Model 20 is good if you install 1-piece axles and truss the housing all the way out to the end of the tubes. I've seen one bend at the outer end outside its existing truss. No jumping was involved but some serious bolder crawling was. Vehicle was a spring-over YJ with 35" Swampers and a V8.

 

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i don't know about 76, but in 77 to around 81, the 3.55 was the common gear ratio.

 

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I know a lot of people (Overland Jeepers of Maine jeep club) that are running 36" Swampers with the AMC 20 and 1-piece axles. Quite a few are also running the 3.54 gears, that way it'll get them down the road without any problems and the T-18/D300 has plenty of low end for wheeling.

JEEPN
'97 TJ Sport
'81 CJ-8 Scrambled!
'71 Commando SC-1
'51 CJ-3A
'47 CJ-2A
 

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If it ain't broke don't fix it. You can quote me on that... LOL... I say that as I try to figure what upgrade is next... gears for me and guess what they're not broke. Jeepers, go figure

 

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Gotta put in one vote for the full floater axle kit rather than the one piece, but it's expensive.

 
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Discussion Starter · #15 ·
I have the moser solid axles in my cj-7 with a 300 HP 350 engine behind them and through light/moderate wheeling....I have had no trouble. The solid axle conversion is much more economical than swapping out drivetrain.

I'm not afraid of dying...I'm scared of not living

chevy-Cj-7
 
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Discussion Starter · #16 ·
I ran the AMC 20 (with one piece axles and locker) with a 330hp 350 V-8 and 35" BFG MTs for a while without damaging it. I do some serious rock crawling, not to mention the occassional dusting of a Mustang at a streetlight (don't worry, I don't do anything stupid; the guy almost always sees he's gonna loose after 100 yards or so and if he don't back off after reaching the speed limit, I do) and never had any problems. My problem was with the D30. With high hp, a locker, and big tires (or any of the above), you need something bigger. I swapped in uncut front and rear Scout D44s after I broke the passenger side axle shaft and hub assembly (the only thing holding the wheel on was the tie rod, it was real ugly!). I only swapped the AMC 20 because I wanted to go wider and the D44s were cheap. I have room for 38s, so after college, I will be doing a frame up restoration and will add a D60 or Corp. 14 bolt. I'll let all of you know when my 4.10 geared, Detroit locked Scout D44 is on the auction block.

 
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