Rear axle upgrade

[bearsden]

What is everyone using to up grade there rear axles now? I am looking to up grade and could use some input.I do see options out there but not sure about quality and all that.I have been doing some reading and from what I gather its a good idea to go to the one piece rear axle kit.I have a 1986 CJ7 and its the AMC20 from what I can tell.

 

[BIGTRUCKNUT]

You sure it's an AMC20 axle and not a Dana 44 ? Most of the '86 CJ7s came with the Dana 44 . As to upgrades, what are you thinking about - regear, differential upgrade to Limited slip or locker, strengthened one piece axle shafts, full floating axleshafts and locking hubs, disk brakes, axle assembly swap? Tell us what the issues are with your current axle, what you plan to do with your Jeep, and/or goals and we can make appropriate suggestions and recommendations. Also, what is your budget? The sky is the limit!

 

[Old Dog]

I'm not sure if we are asking about up grading the 20 or are we asking about a whole different rear end, or maybe both.

 

[Lumpy Grits]

Post a picture of your rear diff cover. Most of the 86's I have seen, had 44's.
IMHO, the best thing for the '20' is the trash can.
The model 20 rear just ain't worth the trouble.
Put a Currie 9" in mine 22years ago. Some of the best $$$ I ever put into my Jeep.
LG

 

[BusaDave9]

The Dana 44 is easy to tell from an AMC20
The AMC20 has a very round cover like this:

The Dana 44 looks like this:

We need to know what you have before we make a recommendation.
http://www.jeep-cj.com/forums/f105/cj-axles-12186/

 

[1986cj7]

Post a picture of your rear diff cover. Most of the 86's I have seen, had 44's.
IMHO, the best thing for the '20' is the trash can.
The model 20 rear just ain't worth the trouble.
Put a Currie 9" in mine 22years ago. Some of the best $$$ I ever put into my Jeep.
LG

Most 86's came with the AMC20 . It wasn't till closer to the end of the production run when they ran out of, or had trouble getting enough AMC20 's to finish the year and went to the Dana 44 . Could be most owners swap out the 20 for a 44. I see this all the time about the 20. Imho If you are going though the trouble of taking the axles out from under the jeep. It's just as easy, maybe about the same price, not sure, to replace the axles with one piece axles, weld up the tubes to the diff, weld on a truss and you have a better axle then the Dana 44 with the ring and pinion being bigger the the Dana 44 . The Currie 9" may be better that I don't know. But the AMC20 in stock form is very weak but can be made to be better then a Dana 44 . Just my .02

 

[Old Dog]

If we are just talking AMC20 axle up grade, I'd stay away from the overseas axles and go with Moser, made here in the USA.

IMHO any axle should have the tubes welded and a truss.

I'm not sure if the 3/8" difference in dia. (8.875" / 8.5") of the 20 ring gear is enough to make any strength difference but the 20 pinion is 1.625" compared to 1.375" of the 44 so the 20 is stronger there, although the newer HD44's have the same 1.625 dia. pinion. Than there's the axles the 20 can only be had with 29 splines while the 44 comes with 30 and can be up-graded to 33 splines. Kinda comes down to what you want to be stronger, the pinion or the axles.
As for swaps I think the 8.8 should be included as it has a 8.8 ring gear, 1.625 dia. pinion. 31 spline axles with 33 spline up-grades. comes stock with disk brakes .
The 9" has so much aftermarket support that almost anything is possible up to 40 spline axles.

 

[IOPort51]

If I suddenly became rich and foolish and could have any axle (s) I wanted it (they) would be 9" fords (both ends). Even if they had to be custom built. If for no other reason than the removable "chunk" I think they are the best designed axles around.

If you will not be running anything bigger than 33" tires I would go with the one piece axles with welded tubes and a decent locking differential.

 

[Posi]

I have a 1986 CJ7 and its the AMC20 from what I can tell.

1) Dave posted pics of the axles, which one do you own?
2) Tell us how you will be using your Jeep, road/class VI, mild trails, or hard trails?

If you plan to use your Jeep on pavement and class VI roads your AMC20 /Dana 44 will work just fine in stock form. If you plan to do harder trials we can help you in the decision making.

 

[Jimbos76cj]

Its a shame the tubes on the 20's are so weak and crappy.. Ive had the privilege to hold a set of 20 and 44 gears in my hand at the same time and I was blown away at how much beefer the 20 gears are.

If your not gonna get crazy with tires and motor I would polish up that 20 with new one peice shafts, weld the tubes and a good truss.. It should last for a long time. If your needing to upgrade to higher spline count due to huge tires and big motor start looking for a 9" rear.

With the Yj's the ford 8.8 is a common swap. I know the bolt pattern is not the same but Im sure some one makes a shaft with the 5x5.5 bolt pattern. there are pretty stout with a 3" tube, I think 31 spline shafts, disc brakes with built in E-brakes and most come with LSD's very easy to find 3:73 and 4:10 geared units.

quick look and found this
Baseline 4x4 Outfitters - YA WF88-31-KIT - Yukon Gear Ultimate Ford 8.8 4340 Chromoly C-Clip Eliminator Kit, 1995-2002 Ford Explorer Rear Axles

 

[Jimbos76cj]

Oh the cheaper option is to get a 4.5 to 5x5.5 adapter for the rear and spacer for the front.. just an idea..

 

[PaRenegade]

After spinning 2 of the 2pc. axles, both while on pavement, I switched to a Moser 1 pc. and haven't looked back since. That was over 20 years ago. Recently during my rebuild I added a truss and had the tubes welded better. (they were factory plug welded) Removed the TrakLok and installed a Detroit.
I think the AMC20 gets a bad rap a lot of times because it's not a bad axle once it's major deficit is fixed (the 2 pc axle/hub).

 

[Al Lindner]

After spinning 2 of the 2pc. axles, both while on pavement, I switched to a Moser 1 pc. and haven't looked back since. That was over 20 years ago. Recently during my rebuild I added a truss and had the tubes welded better. (they were factory plug welded) Removed the TrakLok and installed a Detroit.
I think the AMC20 gets a bad rap a lot of times because it's not a bad axle once it's major deficit is fixed (the 2 pc axle/hub).

Weld the tubes maybe a truss but the ring and pinion on a AMC20 is beefier. A one piece set up is the way to go Me personally I bought the cheaper foreign stuff cause I'm a tightwad and I don't plan on beating the snot outta my CJ ( the key phrase is PLAN ON)

 

[danray48]

Ok gentleman.. I haven't begun to get to the rear axle yet. I have the AMC20 . I understand and have read about the 1 piece upgrade axles. But what is this welding the tubes and adding trusses?. I'll do a search on here, I'm sure it's been discussed on here. If someone would have a pic handy that would help.

 

[DHugg]

Ok gentleman.. I haven't begun to get to the rear axle yet. I have the AMC20 . I understand and have read about the 1 piece upgrade axles. But what is this welding the tubes and adding trusses?. I'll do a search on here, I'm sure it's been discussed on here. If someone would have a pic handy that would help.

Danray, I'm using Superior one-piece axles on my AMC20 under a CJ7 AMC 304 w/35's. I am not a Wild Man in the Jeep; fixing broken stuff is going backward, to me.

Having maximum rigidity in the rear of the drive train will likely save a u-joint down the road.

Good luck!

 

[danray48]

Danray, I'm using Superior one-piece axles on my AMC20 under a CJ7 AMC 304 w/35's. I am not a Wild Man in the Jeep; fixing broken stuff is going backward, to me.

Having maximum rigidity in the rear of the drive train will likely save a u-joint down the road.

Good luck!

DHugg, That looks great. Question, without going out to look right now and it might be a stupid question, but wouldn't that hit the tub if you hit a few bumps? And that is the truss correct? Thank you for the pics, it will give me something to think about in the future.

 

[Old Dog]

Ok gentleman.. I haven't begun to get to the rear axle yet. I have the AMC20 . I understand and have read about the 1 piece upgrade axles. But what is this welding the tubes and adding trusses?. I'll do a search on here, I'm sure it's been discussed on here. If someone would have a pic handy that would help.

The AMC20 has thin axle tubes and they are pressed into the carrier and than plug welded.
By welding them to the center cetion and using a truss it will keep them from twisting or bending like this.
I would also replace the weak spring pads while you have it out.

 

[cj7inthetwigs]

The AMC20 has thin axle tubes and they are pressed into the carrier and than plug welded.
By welding them to the center cetion and using a truss it will keep them from twisting or bending like this.
I would also replace the weak spring pads while you have it out.

Not sure if you're still looking to upgrade. If so you might save some cash. There is a guy named Jody on ATLANTA,GA Craigslist...currently he has a yeelow CJ7 ...... check it out....AMC20 axle work,4?? Gears and an arb locker for $750 . Also the matching front in a amc 30.... actually a boatload of parts for a reasonable price...passing it along since I can't buy it

Sent from my DROID RAZR HD using Tapatalk

 

[danray48]

The AMC20 has thin axle tubes and they are pressed into the carrier and than plug welded.
By welding them to the center cetion and using a truss it will keep them from twisting or bending like this.
I would also replace the weak spring pads while you have it out.

Thanks Old Dog. That explains it on welding the tubes.

 

[PaRenegade]

I'll add another picture to the mix. The truss is made with 5/16" plate with another 5/16"x1" strip added along the top edge. The tubes are welded in 3 spots around the intersection about 1 1/2" each.