AMC20 Pros/Cons?

[irbob]

Lets here it for this diff. Likes/dislikes. I've got one as do a bunch of u but I don't know to much about it.

Whats a good way to lock it?

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My FSJeep Site (http://fsjeep.homestead.com) <----Click one of these----> IFSJA Sticker (http://fsjeep.homestead.com/stickerpage.html)
http://FSJeep.homestead.com/files/Sig_Pix/sig_pic.jpg
"Mystery Machine",360,K&N,TFI,Custom Turbo II 2.5" Exaust,999 Auto,NP229,F/Dana 44F,R/AMC20,32X11.5 Cooper Wildcat MT's,RS 9000's,AALx4,2" blocks,3" Body Lift.

[scotty]

its every bit as strong as a d44. the axleshafts are just a tiny bit smaller,but the ring gear is bigger,as is the pinion. i have run 38 inch tires for a couple of years now,and have hardly had any trouble out of mine. i did somehaow break the crosshaft that olds the spider gears,but i consider this somewhat of a fluke,and not due to a week axle,since i havent had any trouble prior,and have even been running it welded,with 38s,since then,and still havent had any trouble. ive put alot of street miles on it,and the axleshafts are not starting to twist yet. if i could trailer my beast to the woods,i believe i could continue to run it indefinately with no prollems,even with it welded,and 38 in tires.

the only real con is the ground clearnace. the big,round,goofy diff eats up alot of clearance. thats one reason im swapping mine. if i could find a widetrac amc 20 wit the same offset as the QT 44 ill be usig,id have no prollem with clearanceing some of the diff and running it.

whats the best way to lock it? an ARB would let you drive normally on the street,and have a 100% spool when you needed it,but then you have the associated troubles of airlines and blowing o rings,etc. the new cable locker may be a good deal,but they just came out(dont even think they make it for the amc 20 yet) so its hard to comment on that.

if you want a limited slip,a trac lok is inexpensinve and rebuildable,but isnt a wholelot better than an open diff in extreme situations,IMO. an auburn gear would be good,but is a cone style and when its done,you have to toss it and buy another. i think the best limited slip would be the detroit true trac. gear driven,and strong.

as for aut lockers dont even consider a lockright,EZ,etc. if you want an automatic locker,go with a detroit. it may cost alittle more,but youll have it for life http://www.ifsja.org/ubb/smile.gif


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scott
85 grand wagoneer
258 with motorcraft 2bbl/t18/spicer 18 with pto/dana 44/welded amc 20
38x15.5 gumbo mudders
snorkel/dual batteries/onboard air/"custom" convertable
3 inch body lift/mostly stock suspension/"modified" fender openings
custom front/rear bumpers and brushgaurd

widetrac offset dana 44s with clearanced center sections and rear discs very soon
BIG tow truck PTO winch and full roll cage install shortly thereafter
4.0 aquired-4.5L stroker someday...

now we can do some 'wheelin!

[WillyPete]

scotty's right, 20's are just as strong as a D44, but ground clearance is an issue (especially with anything under 31"). can't really think of anything pro/con compared to a 44; i like mine.

detroit is what i'd go in for (for a rear AMC20).

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'86 Grand Wagoneer
Sugar (http://albums.photopoint.com/j/View?u=1666079&a=12770766&p=47642337&Sequence=0&res=high) Magnolia (http://albums.photopoint.com/j/View?u=1666079&a=12770766&p=47642335&Sequence=0&res=high)

[This message has been edited by WillyPete (edited May 15, 2001).]

[smithhl]

A very good pro is that wagoneer AMC 20s are pretty common. And most people do not realize what kind of strengh they have, they usually think they have an inferior axle.

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81 Wagoneer Brougham
327 Vigilante T-18 NP-208

74 Volkswagen Sunbug
Superbeetle

95 Olds Achieva
4cyl 5-speed

[irbob]

Thanks for your comments. Sounds pretty good. I better get one of those diff protectors cuz I have slid across some obstacles with it already.
------------------
My FSJeep Site (http://fsjeep.homestead.com) <----Click one of these----> IFSJA Sticker (http://fsjeep.homestead.com/stickerpage.html)
http://FSJeep.homestead.com/files/Sig_Pix/sig_pic.jpg
"Mystery Machine",360,K&N,TFI,Custom Turbo II 2.5" Exaust,999 Auto,NP229,F/Dana 44F,R/AMC20,32X11.5 Cooper Wildcat MT's,RS 9000's,AALx4,2" blocks,3" Body Lift.

[This message has been edited by irbob (edited May 16, 2001).]

[JEEPRZ]

Im not a fan of the M20 cus I have seen so many of them break in CJs. I know the CJ ones have 2 piece shafts, and the SJs are 1 piece, but have you ever looked at a SJ M20 shaft? Its actually a 2 piece shaft which has been welded together. When it comes time for me to re-gear and add lockers, Im either gonna go D60 or D70. That way I wont have to worry about breakage. When it comes to axle strength, shaft size is very important. a 29 spline M20 shaft is only so strong.

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Dave
83 GW
360/727/229
No longer a tow rig...now its buildup time,axle swap and possible coil conversion??
3"lift, 31s, 3.31s, edlebrock intake, cam, TBI, custom DIY exh, rebuilt trans, shift kit and factory aux cooler,modified 229 (no viscous coupling, *improved* vacuum system), lotsa squeaks, leaks, and rattles

[scotty]

the sj amc 20 axle is not a 2 piece welded deal. i admit,you can see splines,and it sure does look like a 2 piece axle,but it is simply how the pieces were cast. you cannot weld the hub to the axle without drastically affecting the strength of an axle. every cj owner that ive seen do it has eventually broken the axle where the hub meets it,resulting in the wheel falling off. definately no good. an axle would not coe this way from the factory.

the diff is the same for a cj,but i can assure the sj 1 piece axle is alot stronger than the cj 2 piece. ive got quite a few street miles on my amc 20 with a welded diff and 38 inch tires. not only have i not broken an axle yet,but upon last dissassembly the shafts are not even starting to twist the splines yet.you should feel it trying to turn. i definately would have spun a hub by now with a 2 piece axle.

not saying that the axles will hold up forever with welded diff and 38s driving on the street,but give it some credit. hate to see you condem the amc 20 cause of its troubles in the cj.

here are some specs,just for s*its and giggles:

pinion diameter:
m20-1.62" d44-1.37" d60-1.62"

pinion spline:
m20-28 d44-26 d60-29

ring gear:
m20-8.87" d44-8.5" d60-9.75"

axle shaft diameter/spline
m20-1.25"/29 d44-1.31"/30 d60-1.30/30


this is,of course,the newer,fine spline 44. the earlier has 1.25 inch shafts and 19 splines.

also,a d60 is available with 1.5 ich,35 spline axles,but those are alot harder to come by. the d60 from the j20 we parted out is the 30 spline,1.30 inch variety.

at any rate,if you consider diff parts,the amc 20 is just about equal to a 60 in every way except ring gear diameter. the d44 is about equal to a d30 in this area,only thing making it better is a larger ring gear.

as for shafts,you only have 1 less spline and .05" less diameter,compared to the d44 and d60. considering numbers alone,you are not a whole lot less likely to break a d60 axleshaft than you are a d44 or amc 20.

another big thing to consider in swapping 1 ton axles(d60,d70,corp 14 bolt) is that the diffs are even bigger than the amc 20 http://www.ifsja.org/ubb/eek.gif this means youll have run a bigger tire to get the same clearance. you are also adding alot of weight.

i thnk its possible to have good performance with a balnce of smaller tire size,sensible driving style,and lightweight,high clearacne 1/2 ton axles. ive been running 38s with 1/2 ton axles for over 2 years now.

ur thots? http://www.ifsja.org/ubb/smile.gif


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scott
85 grand wagoneer
258 with motorcraft 2bbl/t18/spicer 18 with pto/dana 44/welded amc 20
38x15.5 gumbo mudders
snorkel/dual batteries/onboard air/"custom" convertable
3 inch body lift/mostly stock suspension/"modified" fender openings
custom front/rear bumpers and brushgaurd

widetrac offset dana 44s with clearanced center sections and rear discs very soon
BIG tow truck PTO winch and full roll cage install shortly thereafter
4.0 aquired-4.5L stroker someday...

now we can do some 'wheelin!

[This message has been edited by scotty (edited May 26, 2001).]

[Snakeyes_Tx]

I dunno Scott.. I gotta love my 60 http://www.ifsja.org/ubb/smile.gif And I think when I smack them 39x18 ground hawg ii's on there, I'll have plenny of clearance http://www.ifsja.org/ubb/biggrin.gif I'd love to have a 60 up front too.

Now if you *really* wanna go nuts, there's a guy here in town in the process of taking his F-250 Super Duty, and throwing a set of home-brewed axles under it. He's taking a Dana 80, offsetting it, and using 60 knuckles and adding all the necessary turning components for his front axle, and he's also converting the *Massive* Dana 135 used in F-550's to a single wheel version for the rear.

Methinks this will end up being a smaller version of a monster-truck for the tough-truck competitions.



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http://www.virtue.nu/yazahx/rand/sig.jpg

Snakeyes_Tx
86 J-20 "The Rusty Dinosaur"
360/727/208/44HD/60 <- 2nd of all of them.
"If you don't know what the numbers mean, you don't need to be here!"

[scotty]

i betcha i can go thru a deeper set of ruts with my offse d44 than you can with a d60,even with a bigger tire. in order to get back the 2 inches or so that you lose to the d60 from a d44,youll need to run a 4 inch bigger diameter tire. http://www.ifsja.org/ubb/eek.gif

a friend of mine used to go thru about the same ruts with 33s and an offset 44 as i did with 38s and an amc 20 http://www.ifsja.org/ubb/eek.gif

if ya dont believe me,bring it up to indiana and well play alittle follow the leader http://www.ifsja.org/ubb/biggrin.gif

in all fairness,tho,im a firm believer in finesse,following the right line,and low gearing and low power. there are lots ways to skin the cat,if youre a "foot to the floor" type of wheeler,maybe you need the biggest axles you can get.alot of people fix stuff before its broke. when i starteed wheelin mine i said as soon as the amc 20 broke,id put in a corp 14 bolt. over 2 years later i m still using it http://www.ifsja.org/ubb/smile.gif ive gotten 2 sets of spare axles that ive never had to use for various parts trucks.

dont mean to imply not to use a d60,just that the amc 20 is stronger than alot of people give it credit for,and that 1/2 ton running gear is not neccessarily so horrible http://www.ifsja.org/ubb/wink.gif



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scott
85 grand wagoneer
258 with motorcraft 2bbl/t18/spicer 18 with pto/dana 44/welded amc 20
38x15.5 gumbo mudders
snorkel/dual batteries/onboard air/"custom" convertable
3 inch body lift/mostly stock suspension/"modified" fender openings
custom front/rear bumpers and brushgaurd

widetrac offset dana 44s with clearanced center sections and rear discs very soon
BIG tow truck PTO winch and full roll cage install shortly thereafter
4.0 aquired-4.5L stroker someday...

now we can do some 'wheelin!

[WillyPete]

scotty: when you say you welded your AMC 20, do you mean welded the carrier so it's like a spool, or welded something else (axle to hub?)?

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'86 Grand Wagoneer
Sugar (http://albums.photopoint.com/j/View?u=1666079&a=12770766&p=47642337&Sequence=0&res=high) Magnolia (http://albums.photopoint.com/j/View?u=1666079&a=12770766&p=47642335&Sequence=0&res=high)

[Snakeyes_Tx]

Welded spiders.. like a a spool... no need to weld a one piece axle.

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http://www.virtue.nu/yazahx/rand/sig.jpg

Snakeyes_Tx
86 J-20 "The Rusty Dinosaur"
360/727/208/44HD/60 <- 2nd of all of them.
"If you don't know what the numbers mean, you don't need to be here!"

[WillyPete]

so the diff wouldn't allow the axles to turn at different speeds... and he can drive around town in this setup? wouldn't that snap a shaft pretty soon?

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'86 Grand Wagoneer
Sugar (http://albums.photopoint.com/j/View?u=1666079&a=12770766&p=47642337&Sequence=0&res=high) Magnolia (http://albums.photopoint.com/j/View?u=1666079&a=12770766&p=47642335&Sequence=0&res=high)

[Snakeyes_Tx]

Just more proof how tough AMC 20 axle shafts are! I doubt he drives too many miles on the street (Hey Scott, is that thing even street legal the way it is??). He's even mentioned that the splines on the ends of the shafts aren't even starting to twist yet.

On most axles, you're absolutely right... it'd snap quite quickly... I think a combination of little street miles, and tempting fate is also part of his success on that rear! http://www.ifsja.org/ubb/smile.gif


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http://www.virtue.nu/yazahx/rand/sig.jpg

Snakeyes_Tx
86 J-20 "The Rusty Dinosaur"
360/727/208/44HD/60 <- 2nd of all of them.
"If you don't know what the numbers mean, you don't need to be here!"

[Slippery]

WillyPete: just in case you haven't seen it...
http://pacifico.off-road.com/~wagoneer/wild/scott_probert/

There is a license plate screwed to the tailgate, but I seriously doubt it sees street duty. (And what's up with that "Chevrolet Power" decal?)

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Jason K.
http://us.f1.yahoofs.com/users/e46e6dee/bc/My+Photos/Festiva.jpg?bcw0GX7Ax3rIxilV
'88 Ford Festiva
40mpg work car
Cost $150, paid for itself already
------------------------------
'90 Chevy Lumina
Biggest POS in the 115-year history of the automobile
4 cylinders, less than adequate for a car half its size
Crappy rear disc brakes, $19M class-action lawsuit settled
------------------------------
Some other junk not worth mentioning

[This message has been edited by Slippery (edited May 26, 2001).]

[WillyPete]

dayumn. forget i said anything about axle snappage. that is one serious wagoneer you have there my friend.

nice work on the... well, everything http://www.ifsja.org/ubb/smile.gif.

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'86 Grand Wagoneer
Sugar (http://albums.photopoint.com/j/View?u=1666079&a=12770766&p=47642337&Sequence=0&res=high) Magnolia (http://albums.photopoint.com/j/View?u=1666079&a=12770766&p=47642335&Sequence=0&res=high)

[WillyPete]

where's your gas tank?

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'86 Grand Wagoneer
Sugar (http://albums.photopoint.com/j/View?u=1666079&a=12770766&p=47642337&Sequence=0&res=high) Magnolia (http://albums.photopoint.com/j/View?u=1666079&a=12770766&p=47642335&Sequence=0&res=high)

[scotty]

it is by no means a daily driver. however,until recently the only way to get it to the woods is to drive it on the street. haspin acres is 70 miles each way. ive got 2 trips there,a couple local trips to middletown,which is 20-30 miles away,plus quite a few trips back and forth to work,meijers,etc.

i can drive it around town,but it makes me cringe.when i turn,the tire doesnt just happily bark and scuff like the 31s did on my eagle.100 lbs of 15 inch wide ground hawg has alot more traction than a little 31x10.5,and you can feel it. i can picture the axle twisting up like a twizler in there. but it has held up so far. i agree that the street will kill it sooner than later,but i do think that if i trailer it to the woods that i could run the welded diff almost indefinately. mud and dirt are much more forgiving than pavement.

yes it is street legal,tho it wont pass e check.no cat. i have finally obtained a 74 title to get plates with no e check http://www.ifsja.org/ubb/biggrin.gif

the chevy power sticker was in an assortment pack from summit. i stuck it on there cause a) i had it an it looked cool http://www.ifsja.org/ubb/smile.gif and b) at one time,a very long time ago,i actually thot that it wouldnt last long and when it blew up id drop in a small block. well after much abuse it finally took freezing to kill the little sucker(well,actually it does still run with a big crack in the block) and yall know my thots on the amc 6 now.

willypete,thanx for the compliments,hopefully the next batch of pics will be equally as impressive,since the drivetrain pics are now obsolete. soon will have pics of new 258,t18 and spicer 18 with pto,and new widetrac d44s with offset rear and rear discs.

the gas tank in the pics actually were the 2 red cans behind the front seats http://www.ifsja.org/ubb/redface.gif bt that was a temp thing. the tank is a big retangluar one(not sure what its from),and is now located in the bed behind the roll bar. its a good thing,cause there definately wouldnt be room for the pto and linkage with the factory tank!

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scott
85 grand wagoneer
258 with motorcraft 2bbl/t18/spicer 18 with pto/dana 44/welded amc 20
38x15.5 gumbo mudders
snorkel/dual batteries/onboard air/"custom" convertable
3 inch body lift/mostly stock suspension/"modified" fender openings
custom front/rear bumpers and brushgaurd

widetrac offset dana 44s with clearanced center sections and rear discs very soon
BIG tow truck PTO winch and full roll cage install shortly thereafter
4.0 aquired-4.5L stroker someday...

now we can do some 'wheelin!