The AMC 20 rear

I came across an AMC 20 from a late 70s jeep. I think the gears are 351 or something. this axle is teh two piece hubs with teh keyways. So I really stay away from it, or is it true that if you keep teh outter nuts tight , they will hold up iunder light loads. My project will have a beater small block in it, and I was thinking that its a cool rear because of teh whole jeep rear width deal. Any and all comments appreciated.

Pork

 

that's a pretty light duty rearend, I'd keep looking

 

+1

My old man used to kill them in the woods all the time...I seem to remember them always spinning in the hubs?
Thats why I liked my Bronco's!
V-8 + a 9" and a 44 out front.

 

I've had a bunch of big jeeps, including two full size cherokees and a grand wagoneer which all had AMC 20s. But they were the one piece units. I ran those HARD offroad with 33" tires and built 360s. The rear held up just fine, even pushing 4,000+ pound vehicles over big rocks.

The two piece isn't as strong, but I wouldn't call it "light" duty. If you're not building a torque monster motor and aren't trying to put it in a 4,000 pound car, you'll be fine. What's the application?

 

Some drag racers "back in the day" would cut an extra keyway in the shaft to help it out. One piece axles will work better. They may be "light duty", but they will take a lot of abuse- I've seen stock axles in some otherwise well built Jeeps do some unreal things off pavement. If you've got it use it; you shouldn't have any problem.

 

wow, weak, I don't think so with a beater chevy motor...3.54 is probably the gear ratio...I like using them in a traditional car because of the hubs, and if your not putting a set of sticky's and trying to run sub 12 seconds you will have no problems with this rear end.......

 

Well, like any part, there is the good and the bad.

The ring and pinion are larger than a dana 44

The 2 piece axles can slip, but there are 1 piece parts available.
I've welded everything up (nut included) and they lived for quite a while.

The tubes can spin inside the center chunk, but nuthin more welding can't fix.

If it's free I'd run it in a heartbeat.

 

Thanks all, for the comments, I seem to have a 50/50 on go or throw. Not persuaded just yet to make a decision. I have heard that people weled teh nuts and all of that. I guess teh rouble with the welding all together, is :would it be a problem yanking them after the split or crack with all welded? I know it's a posi unit, and I also know it is a 5 on 5.5.5 bolt pattern, which matches my frontend. TO teh top and more reposnses if you have em
Pork

 

the AMC (****er) 20 is not a strong rear end. The axels are week . I've seen them broken with six cylinders in jeep CJ's . I wouldn't waste my time with one. By the time you spend money for one piece axels and weld up the center section you could have bought a good 8.2 or even a 8 1/2.

 

Agreed. The AMC 20 can be beefed up with aftermarket parts, but the one thing that can't be upgraded are the axle tubes (actually, I think there is or was a company making thicker tubes at one point, but if you go that far, get a 9"). With abuse they can bend, but it's mostly an off road hazard-although I'm sure someone on the street could pretzel one somehow.

 

Nope, you pull the axles without undoing the flange nut [EVER] so being welded is not a problem there. The 2 piece axle is a cost saving thing (easier to make)

LOL I know a guy who blew up a 14 bolt once, 1 ton PU small block on the street!
Mang that guy could **** up an anvil with a feather in a padded room

 

I snaped a 14 bolt axel at the drive flange once....thats what Budweiser, an aluminum headed small block and fourty inch tires will do.

 

Case in point ^^^^

LOL

Back to the original question.

If it's the right width, and it's a reasonable price, and it sounds like the bolt pattern is correct, I'd run it.

There not really "bad" axles. Guys spin the outer hub with low range, big tires and low gears.
IIRC the did make some dana 44 axles in those years. They would be the same width as the 20 your looking at. Prolly a little tough to find as they were an optional upgrade and all the 4x4 guys are gobbling them up.

 

there are alot of after market parts for them.gears from 2:73= 4:88.detroit ,loc-rites ,ARB lockers & posi's..afew companys make one axle kits for them..weld up the tubes and they will handle alot . your just polishing a turd though.....

 

Sadly I don't think there are anymore "junk" early Bronco's out there, but if you DO run across one, the 9" in those is a very similar width to a Jeep and we all know how good 9"ers are.

The Scout 800A has a similar width to a Jeep as well. I THINK they came with the Dana 44's... I know the Scout II did on both ends, but that's quite a bit wider than a Jeep.

Good luck.

-Chris

 

Thanks all, I did forgot to menion, this thing is a factory posi set up
! I think I will weld the tubes, weld up the nuts on the axles, change teh pumpkin oil and use her till she pops, then replace teh axle that goes first, if it even goes. This will be a 1500pound car when I am finisihed, and teh engine, although a small block will not excedd 300 horse. For 50 bucks, to have a 354 posi rear with that jeep width, I'm startin to think its worth the risk. Pork