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A stock AMC J20 rear end ??


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In 1987 literature (AMC's last year :( ) the D44 was listed as part of the Off Road Package, part of the HD Towing Package, part of the Metric Ton/Big Ton Package, and as a stand alone "HD rear Axle" option.

 

Things were good, for one year atleast.

 

After that it was officially dropped from all, but the Metric Ton/Big Ton option (tho some non-MT MJ's did seem to come with them after 87', 87' is still the most common year for XJ & MJ D44's).

 

 

AMC M20 vs D44:

 

8.875" ring gear (same size as a 12 bolt Chevy) vs 8.5"

29spline (but bigger than 8.25's 29sp) vs 30 sp shafts.

 

There are other strength comparisons, like the M20 using less ring gear bolts, and a crush spacer for pinion preload (vs an XJ/MJ D44's solid shimmed pinion).

M20's have been known to spin tubes in the axles, and parts can be less common, but they're fairly close to a wash strength wise.

 

All that said, I would not pay $500 for an MJ M20.

I would consider it in the $200-$250 range, but only because the 4.10's MJ 20's came with are decent, and it's a pretty good swap into an AMC car.

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Sorry, but that's not correct. The Metric Ton package wasn't offered on the shortbeds, but the D44 axle came with other packages. I have an '87 shortbed that I bought from the original owner's daughter. It's all stock, and it has a Dana 44 rear axle -- with Trac-Lok.

 

Thanks for playing. Nah, that is a common belief, that ONLY metric ton MJ's came with D44's, but that is untrue. It was a selectable option, even in shortbed trucks, and often found its way on to the shortbeds in the form of towing packages. There are actually a few members here who have SWB MJ's and D44's from factory. They seem to be even more prevalent in the later years '91-'92, possibly because Chrysler was burning up stock of them.

 

Rob L. ;)

 

EDIT: Eagle beats me again. 8)

 

Sorry about that. I guess that just shows that you learn something new everyday. I thought the D44s only came under Metric Tons. I didn't know it was an option under some packages with a shortbed. I guess I better go read my 1987 Jeep Comanche brochure and look at the option packages.

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an AMC20 that is FROM an MJ is about equal in strength. CJ guys are desperate to get them as they're better than the C20 offered in CJ's...same axle, save for the fact that the MJ uses one piece axleshafts rather than the 2 piece shafts of earlier AMC20's.

 

 

given the choice, I'd use a d44 for the fact that aftermarket parts are more available. but for the right price (under $300), I'd buy an amc20 that's already got 4.10's in a heartbeat, install it, and not think twice about it.

 

 

I have an amc20 in my 86 comanche diesel...almost 300,000 on it with original bearings and no issues....but the motor makes 85hp so I wouldn't expect to have issues lol

 

 

-Pat

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Thats what I thought ! Isn't the 44 easy to find replacement parts for , long term !!

I have no idea of the splines. My dana 44 was out of a 89 xj W / towing pack. I thought it was stock at first, but after

more inspection , I found the mounts had orig. been sprung over .

 

I just wanted to let you know that your Comanche couldn't have came stock with a D44 anyways. There were no shortbed Comanches that came stock with a D44. The D44 came stock under the Metric Ton Comanches and all Metric Ton Comanches are longbeds. I hope this info helps.

Sorry, but that's not correct. The Metric Ton package wasn't offered on the shortbeds, but the D44 axle came with other packages. I have an '87 shortbed that I bought from the original owner's daughter. It's all stock, and it has a Dana 44 rear axle -- with Trac-Lok.

 

 

Eagle, I second, third, and fourth you on that fact. I've owned 3 shortbeds that came factory with d44's, and are factory on their build sheets...one of them was 2wd as well, and a base model.

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The guy wants 500.00 cold !! I don't know if thats worth it ? It looks to be in the same condition mine is in , ( needing rebuilt )

so I think I'll stick w/ the xj d 44 .

I've bought complete XJ's with both 44 and 20 and drove them home for less than $500. Prices vary around the country but in this area a good D44 can be picked up for less than $100. Same for the C20.

 

xj's never came with amc20's from the factory...and that is a solid FACT.

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yes, but they can be swapped in. :dunno:

 

 

ok. realistically, how many xj's do you think you're gonna find for $500 that someone took the time to swap an amc20 into?

 

 

....slim to none.

 

 

based off that deduction, I assumed he was referring to amc 20's and that they had come stock in the cherokees...which is NOT possible. that is one absolute, 100% guarantee with AMC.

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Axles out of J20's are 8 lug.

My bad. I thought that was only on the J30

 

Nope. J30 and M715 came with Dana 70 rear and D60 closed knuckle front.

But the J30 axles are 8-lug. I had just forgotten that the J20 axles were also 8-lug.

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OK..Ya'all got me on the XJ C20. Was to quick to post a reply without thinking. But I know 2 of them did have the D44 cause after I got them home I took 'em out. Got 7-8 out there don't know what's under them. Know one got a D44, I looked. Not sure about the others tho. Chrysler 8"? :fool: image_209027.gif

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M715's weren't 8 lug. (6 lug on 7.25").

 

76 J20 axles would be pass drop D44ft /30sp ff D60 rear.

Drivers (left hand) drop FSJ axles didn't start till the 1980 model year.

3.73 was the most common J20 ratio.

 

1973 & older FSJ's were available with a DRW D70, but the fts were closed knuckle D44's (except for the M715).

This adapter:

was used upfront to match the D70 width & patturn.

 

J10/J20 designations started in 1974 (J300, J3000, J4000 etc were the designations were used before that).

I've never seen a 'real' J30, but if they did get ft 60's, it would've likely been an open knuckle 60, since FSJ's dropped closed knuckle ft ends after the 1973 model year.

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Well I run the "MJ" AMC 20 axle. it is 29 spline but really.. what is one spline count gonna do? nutin.. the shafts are same size as the 44 and the tubes are much thicker than the old cj style units so the weak tube story is incorrect. the MJ axle is just like the FSJ model just sized for the MJ. it is not worth $500.00 in my opinion, and unfortunately you can't just go order extra shafts for it if you want like you can a 44. so if you have a 44 your good. I think I paid 150.00 for mine. I locked it and its been getting the job done for several years now.

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