AMC-MJ Posted February 7, 2010 Share Posted February 7, 2010 Right now i have a n AX-4, Dana-35,3.73's and 225's = 65mph@3,000rpm in 4th-DD. I'd like to run an AX-5, AMC-20, 4.44's and 235's = 70mph@3,000rpm in 5th-OD. Some have suggested i go to 4.56's other say 4.10's well with the AMC-20 axle i can get a 4.44 gear set and be right between the suggested gear sets :clapping: thought's ? . . . I can get the solid 1 piece axle for the AMC-20 fixing its issue with the axles and the A20 has to be a good bit better then the D35 ? thought's ? Mike Link to comment Share on other sites More sharing options...
Pete M Posted February 7, 2010 Share Posted February 7, 2010 what did this AMC-20 come from? Link to comment Share on other sites More sharing options...
AMC-MJ Posted February 7, 2010 Author Share Posted February 7, 2010 I was hopping to snake one from an AMX or Javelin as they are set up the same with the axle on top the spring . . . Mike Link to comment Share on other sites More sharing options...
Geonovast Posted February 7, 2010 Share Posted February 7, 2010 Perch location is the last thing you want to be worrying about when picking up an axle. Not only will they most likely not be the correct width, but your pinion angle will also most likely be off. I seriously doubt the AMX/Javelin 20s are the same width as an MJ one. Link to comment Share on other sites More sharing options...
CWLONGSHOT Posted February 7, 2010 Share Posted February 7, 2010 The AMC 20 is a good axle and the two piece axles much like the dreaded "C" clip get a bad wrap. Its mostly unfounded, again, if the axles are properly torqued and watched, they will not be a problem. No one wants to take responsibility and blames the problems on a "weak" axle. It has a good sizes gears and bearings and 29 spline axles. Its housing is its real weak spot in my mind. Its stronger than the D35 and likely on par with the XJ D44. What gear to run is determined by a number of criteria. Tire size, transmission and motor. Then what your doing with it and if you have done anything to the T case gearing. With a 4.0; 3:73 to 4:10 are good for 31"s - 4:10 to 4:56 for 33's - 4:56 to 4:88 for 35's. Lower number for a stick and taller for the Auto. With a 2.5; 4:10 to 4:56 for 31's - 4:56 to 4:88 for 33's - 5:38 to 5:89 for 35's the Lil 4cl really looses it with the big tires. CW Link to comment Share on other sites More sharing options...
Pete M Posted February 8, 2010 Share Posted February 8, 2010 I was hopping to snake one from an AMX or Javelin as they are set up the same with the axle on top the spring . . . Mike What are the widths and wheel bolt patterns? Link to comment Share on other sites More sharing options...
AMC-MJ Posted February 8, 2010 Author Share Posted February 8, 2010 They have a larger ring gear . . .Specs i found, Model AMC-20: Ring Gear Diameter: 8 7/8" Pinion Shaft Diameter: 1.625" Ring Gear Bolts: 8 Right Hand Threads: 7/16" x 20 Pinion Splines: 28 Cover Bolts: 12 Bolt circle: 5 x 4.5" Year range / Vehicle : 68-74 Ambassador. 68-79 AMX. 68-74 Javelin. 70-76 Gremlin. 70-77 Hornet. 72-78 Matador. 68-69 Marlin. 78-79 Pacer. 68-69 Rambler. 68-69 Rebel. 79 Spirit. 76-86 Scrambler. 80-86 Wagoneer. 80-86 J/10. 79-06 Hummer H-1 center section IFS/IRS. It appears to be all the same unit, only there is no mention of usage in the MJ's ? :dunno: ? i can't imagine there all that weak considering AMC used them behind V8's as powerful as the 390 & 401 Crossram's . . . which laid down 11-9 second 1/4 mile times. used in 2,800-3,800lb Car's. used in 4,500lb-6,000lb truck's. which ya know them truck's got loaded some what heavy and towed trailers & got wheeled rather hard with over sized tires. Mike Link to comment Share on other sites More sharing options...
freakjeep93 Posted February 8, 2010 Share Posted February 8, 2010 wasnt the mj one different? Link to comment Share on other sites More sharing options...
AMC-MJ Posted February 8, 2010 Author Share Posted February 8, 2010 I don't really know . . . It just didn't list an MJ or XJ . . . Mike Link to comment Share on other sites More sharing options...
Geonovast Posted February 8, 2010 Share Posted February 8, 2010 It was never in the XJ, and only in the MJ in 86. Some sources say they never got them... but there's too many people, specifically on here, that have them factory in their MJs. Link to comment Share on other sites More sharing options...
Pete M Posted February 8, 2010 Share Posted February 8, 2010 What is the width on those axles? Link to comment Share on other sites More sharing options...
AMC-MJ Posted February 8, 2010 Author Share Posted February 8, 2010 :dunno: you got me :dunno: I could measure my AMX when i'm over by it next ? :thumbsup: Mike Link to comment Share on other sites More sharing options...
Pete M Posted February 8, 2010 Share Posted February 8, 2010 width is important. MJ's have pretty wide axles. Wider than even wide-track Jeep axles. Link to comment Share on other sites More sharing options...
AMC-MJ Posted February 8, 2010 Author Share Posted February 8, 2010 The MJ don't appear any wider then the AMX . . .I could be wrong ? Mike Link to comment Share on other sites More sharing options...
Pete M Posted February 8, 2010 Share Posted February 8, 2010 what the backspacing on those cars' wheels? MJs have a ton of backspacing (5.25 inches) to accomodate those wide axles. Link to comment Share on other sites More sharing options...
AMC-MJ Posted February 8, 2010 Author Share Posted February 8, 2010 4.5" - 5.25" rear and 3.75"-4.5" front depending on rim width . . . Mike Link to comment Share on other sites More sharing options...
jpnjim Posted February 8, 2010 Share Posted February 8, 2010 Those 71+ Javelin rears (AMC 20's) are the same exact width as our XJ/MJ rears: 60". (I posted this in a thread here last week :dunno: ). It wasn't a coincidence either: Hornets & Concords (same body) used 58" wide axles. 71+ Javelins used 60" wide axles. When AMC wanted to make the Concord a 4x4 (Eagle), they needed to rethink axle width & backspacing. The ft WMS to WMS would have to be substantially wider to fit the drive axle components & unit bearings, so they'd have to increase the rear axle width to match (and use deep back spacing wheels ft & rear to put the track width back to near where it was). To the rescue comes the Javelin width 60" axle (in this case the AMC-15 aka: 7 9/16", aka: Dana 35). At the same time they made it SOA to lift the Eagle over the Concord's ride height. When it came time to design the XJ, they started with what they had (Eagle), you can pull an Eagle rear axle out, and sling it right under an XJ. Same width, same bolt patturn (XJ's were the first 5 on 4.5" Jeeps for a reason), same perch location. IIRC, the only difference is the shock mounts are staggered the opposite way. The Eagle ft (IFS) bearing hubs are almost an exact match for early XJ's (XJ's have an additional cover on the back of the same exact bearing), and the rotors directly swap (I got some Eagle rotors cheap at an AMC show and used them on my MJ for years). So, to answer the question, yep 71-74 Javelin rears are 60" wide, 5 on 4.5", and SUA (tho I think the perch width is different, I could measure it :dunno: ). They also have craptastic 2-piece axle shafts (which is why I started this thread last week: viewtopic.php?f=2&t=21315 ) Link to comment Share on other sites More sharing options...
Pete M Posted February 8, 2010 Share Posted February 8, 2010 there you go. :thumbsup: back to the gears issue. I don't know where you're getting the 4.44s, but remember that used gears cannot be guaranteed to not hum when installed in a new axle. Link to comment Share on other sites More sharing options...
AMC-MJ Posted February 8, 2010 Author Share Posted February 8, 2010 4.44 Gears was an AMC factory offered gear for many years and can be had in New Old Stock, used, and in rare case hot off the press new by AMC vendors here n there . . . also offered is a 3.91 ratio which i'm going to in my AMX to replace the 4.44's i already have . . . If i could find an AMC-20 that fit my MJ with 3.91's I'd do a switch o change o of the gearing between the 2 axles AMX get's the 3.91's MJ gets the 4.44's and have both Vehicle's rear end's re-geared and rocking the same diff's with Moser 1 piece axle shafts . . . Mike Link to comment Share on other sites More sharing options...
CWLONGSHOT Posted February 8, 2010 Share Posted February 8, 2010 4.44 Gears was an AMC factory offered gear for many years and can be had in New Old Stock, used, and in rare case hot off the press new by AMC vendors here n there . . . also offered is a 3.91 ratio which I'm going to in my AMEX to replace the 4.44's i already have . . . If i could find an AMC-20 that fit my MJ with 3.91's I'd do a switch o change o of the gearing between the 2 axles AMX gets the 3.91's MJ gets the 4.44's and have both Vehicle's rear end's re-geared and rocking the same diff with Moser 1 piece axle shafts . . . Mike 3:91 and 4:44 are all well and good in a 2WD... but you gotta be able to match (Or come damn close) for the front axle... These are NOT available in or for the D30.... CW Link to comment Share on other sites More sharing options...
CRF136N Posted February 8, 2010 Share Posted February 8, 2010 3:91 and 4:44 are all well and good in a 2WD... but you gotta be able to match (Or come damn close) for the front axle... These are NOT available in or for the D30.... CW x2; furthermore running a 235 tire with the ax5, I would imagine 4:10's would get the job done just fine. As genovast pointed out, I got my AMC 20 rear and matching 30 front with 4:10's (or is it 4:11's?) from a '86 metric ton MJ V-6 2.8; It'll be a direct swap...no guesswork, those seem to pop up every once in a while. Link to comment Share on other sites More sharing options...
AMC-MJ Posted February 8, 2010 Author Share Posted February 8, 2010 My truck is 2WD :thumbsup: i aint got no front end to match up with Mike Link to comment Share on other sites More sharing options...
CRF136N Posted February 8, 2010 Share Posted February 8, 2010 ...seeing as you'll have the tranny out...and the rear axle out...it wouldn't take much more than a transfer case and front axle to solve that :roll: :brows: But hey, I know some of you don't need it...just an idea :D Link to comment Share on other sites More sharing options...
mnkyboy Posted February 8, 2010 Share Posted February 8, 2010 what are you planning to do with you MJ that a D35 couldnt handle? I can't see you breaking one with a 2.5L 2wd unless your planning to desert race it Link to comment Share on other sites More sharing options...
Geonovast Posted February 8, 2010 Share Posted February 8, 2010 what are you planning to do with you MJ that a D35 couldnt handle? I can't see you breaking one with a 2.5L 2wd unless your planning to desert race it The only D35 I've ever had die on me was behind the only 2.5 I've ever had. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now