Locking rear axle

[Bill D]

I have an ARB compressor that will handle the shifting chores plus give me an additional air source for up-airing tires.
I'm not particularly afraid of the ARB reliability. ARB makes a lot better stuff than they used to and they don't seem to have a lot of problems. I guess any shifter type of diff can have it's problems but they all seem to be getting better and better. And any of them are infinitely better than the TrakLoc that I've been living with. And, I have to admit, I've come a long way from when I bought the beast with a Hi Lift jack for a front bumper.

 

[mriplaybass]

Okay, here it is. Not too much doubt now about what rear diff is installed in my AMC20 rear axle. I could go into it and replace/repair but I am told that the life expectancy of the Trac - Lok is about 50,000 miles and since I plan to keep this jeep for a good long while - I decided to just go ahead and bite the bullet. By sometime this afternoon, I plan to have it ready to drive with the two piece axle shafts changed out to one piece, the axle tubes welded to the housing, and a new ARB air-lock locker installed.

Here's a pic of the diff right after poping the cover.

Glad to see you're making positive steps! You won't regret your decision once we hit the trails in Aug. Are you going to install a locker up front?

 

[Lumpy Grits]

Another thing to consider with that '20' rear.
It's the go-kart size brakes that were used.
IIRC-The Dana 44 used in the last of the CJ's had larger brakes.
The 44 also had thicker axle tubes for less axle housing flex.
LG

 

[Woolyworm]

You 20 hater LG! My 20 has served me well.


Wooly

 

[mtnwhlr]

Another thing to consider with that '20' rear.
It's the go-kart size brakes that were used.
IIRC-The Dana 44 used in the last of the CJ's had larger brakes.
The 44 also had thicker axle tubes for less axle housing flex.
LG

You 20 hater LG! My 20 has served me well.


Wooly

The 20 has a bigger ring and pinon than the 44 and can be made to hold up just as well.

 

[Woolyworm]

I've got 11" brakes on mine


Wooly

 

[Bill D]

Glad to see you're making positive steps! You won't regret your decision once we hit the trails in Aug. Are you going to install a locker up front?

I'm for sure not going to have a front locker for a while. Gotta recover from the rear locker first. I need to install new front shackle bushings right now and I think I will do the rear while I'm at it. Just Empty Every Pocket, right?

 

[Lumpy Grits]

You 20 hater LG! My 20 has served me well.


Wooly

Just call'em as I see'em, after work on'em for 35+ years.
The only axle I think less of is the D35 used in Wrangles.

The 20 has a bigger ring and pinon than the 44 and can be made to hold up just as well.

The 20 also has thinner axle tubes and smaller brakes than the Dana 44

I'm for sure not going to have a front locker for a while. Gotta recover from the rear locker first. I need to install new front shackle bushings right now and I think I will do the rear while I'm at it. Just Empty Every Pocket, right?

Think about a LSD for the front. With a real locker in the rear. Your Jeep will want to 'plow' in tight turns and not turn as you would hope when in 4wd.

 

[Lumpy Grits]

I've got 11" brakes on mine


Wooly

What year '20'? OEM brakes?
Don't recall the exact dia of the 20 brakes at the moment.
LG

 

[Woolyworm]

78 switched to 10" from 11"


Wooly

 

[Woolyworm]

I'm 76


Wooly

 

[Lumpy Grits]

78 switched to 10" from 11"


Wooly

AMC 'beancounters' strike again. :laugh:


LG

 

[007]

Ya know the 20 bashing kinda bothers me. It doesn't offend me or make me feel like I need to change because I know better.

But it DOES tell those who are new that their axle is somehow insufficient...when it ISN'T.

Most people just need to make sure that their axles are tight. Others need one piece. Some need to spot weld tubes and rock climbers might want to truss. But just because it isn't the most robust in its stock form doesn't make it junk.

Most 20's on the road have had nothing at all done to them. Doesn't that say anything at all?

No one is suggesting all you 258 owners need swap engines because there's a stronger one out there are they? Nope they aren't. Same with the 20.

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[BusaDave9]

The other thing is Bill already made his decision. I think he made a good decision to install a locker in his AMC20. He is addressing the axle shaft issue with one piece axles. He's getting the tubes welded. He's going to have a damn good axle when he's done. Now is not the time to tell him to get a Dana 44. Now is not the time to go over the other options. He made the same decision I would have made. Actually I was faced with the same issue and kept the AMC20 and improved it like Bill is doing. Back in Minnesota I had a '84 CJ7 and I put in an ARB air locker. I never had any issues with it. Now I have a '79 CJ5 with an OX locker in the AMC20. It's been running good too although I have had to readjust the linkage once because the cable became too loose to lock the diff.
If you make these improvements the AMC20 is a good axle.

Think about a LSD for the front. With a real locker in the rear. Your Jeep will want to 'plow' in tight turns and not turn as you would hope when in 4wd.

The great thing about a selectable locker such as the ARB is you can turn it off for tight turns. Also turn it off on slick roads.

 

[Lumpy Grits]

Ya know the 20 bashing kinda bothers me. It doesn't offend me or make me feel like I need to change because I know better.

But it DOES tell those who are new that their axle is somehow insufficient...when it ISN'T.

Most people just need to make sure that their axles are tight. Others need one piece. Some need to spot weld tubes and rock climbers might want to truss. But just because it isn't the most robust in its stock form doesn't make it junk.

Most 20's on the road have had nothing at all done to them. Doesn't that say anything at all?

No one is suggesting all you 258 owners need swap engines because there's a stronger one out there are they? Nope they aren't. Same with the 20.

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Where I jeep in the Mojave and the trails here have proven just the opposite for the '20'. To many failures to count.
I had so many issues with mine, that I could trust it.
If your happy with your 20. Then by all means enjoy it.
BTW: The ONLY reason I haven't put and '8' in mine is due to the SMOG laws in PRK.
That said-My 6 has served me well for 31+ yrs.
LG

 

[007]

Where I jeep in the Mojave and the trails here have proven just the opposite for the '20'. To many failures to count.
I had so many issues with mine, that I could trust it.
If your happy with your 20. Then by all means enjoy it.
BTW: The ONLY reason I haven't put and '8' in mine is due to the SMOG laws in PRK.
That said-My 6 has served me well for 31+ yrs.
LG

But that's my point. There's nothing wrong with a 258 and for what the VAST majority do there's nothing wrong with a 20.

I wouldn't want a stock 20 in Mojave but I don't believe for a second that a one piece welded and trussed 20 would have a problem there.


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[Bill D]

This '80 model is, what, 36 years old? I'm sure not the first owner and have no idea how many went before me or what they did to the old girl. I know it probably has at least a 3" suspension lift and a 1" body lift and someone installed a set of pretty nice 10" wheels that had 33X12" tires. It has a 4.2 six that runs strong and uses no oil. The 176 transmission had a top that was screwed up so I replaced the top and it shifts just fine right now. No problems with the 300 transfer. I broke a front axle last winter while trying to get a stuck Toyota out of a frozen stream that he fell through. I now know that the AMC20 rear axle was as cherry as the day it was born. It may not have been one of Jeeps finest moments but it went well over 100,000 miles with a Trak-Loc and two piece axles. Not a bad record for a 36-year old that has almost certainly had the driven out of it. Anyhow, I'm happy and I'm sure that I'm going to be happier now with the recent work I've done to it.

I'm a bit curious why LG seems intent in discrediting my vehicle and everything that I have done to it. I certainly would not do that to his vehicle. By the way LG, I know a guy down where I came from that had been a mechanic for 35+ years and he's still just as bad as when he started.

 

[mtnwhlr]

This '80 model is, what, 36 years old? I'm sure not the first owner and have no idea how many went before me or what they did to the old girl. I know it probably has at least a 3" suspension lift and a 1" body lift and someone installed a set of pretty nice 10" wheels that had 33X12" tires. It has a 4.2 six that runs strong and uses no oil. The 176 transmission had a top that was screwed up so I replaced the top and it shifts just fine right now. No problems with the 300 transfer. I broke a front axle last winter while trying to get a stuck Toyota out of a frozen stream that he fell through. I now know that the AMC20 rear axle was as cherry as the day it was born. It may not have been one of Jeeps finest moments but it went well over 100,000 miles with a Trak-Loc and two piece axles. Not a bad record for a 36-year old that has almost certainly had the driven out of it. Anyhow, I'm happy and I'm sure that I'm going to be happier now with the recent work I've done to it.

I'm a bit curious why LG seems intent in discrediting my vehicle and everything that I have done to it. I certainly would not do that to his vehicle. By the way LG, I know a guy down where I came from that had been a mechanic for 35+ years and he's still just as bad as when he started.

I know plenty of people with the AMC20 that have beat the out of them and they are still going me included so don't worry to much about it.

 

[IOPort51]

Do the math. Can you build the axle you want for the same amount of work and money. My rear is a Dana 44 with disks and an OX locker. It was ever so less expensive to having an AMC20 with disks and an OX because I did not need to replace the shafts. I did get a pretty good deal on the axle but it was always just a housing so as long as it was not bent or cracked it made very little difference what shape the rest was in.

Axles are expensive! This is true. Be sure you have totally overthought this because you don't want to do it twice.

 

[mtnwhlr]

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