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how to tell what rear axle I have?


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Hey all, well, on the way home yesterday, I had a loud noise and some "thunking" come from the rear dif, then the driveshaft ripped from the ubolt!!! :mad: so now I'm needin a new rear end, gonna go to the junk yard, so how do i find out what rear end I have? how many did they make for these old jeeps? ( just bought it a week ago so I know nothing about it) thanks

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Chances are real good it's a Dana 35 rear axle. Donors can be found under XJ/YJ/TJ/ZJ/KJ Jeeps. Some are more work than others. Any one of those will need the axle stripped of brackets and new perches welded on in the MJ location. Only an MJ axle will "bolt-in". A Ford Explorer rear axle is also an option.

You'll need to find out what gear ratio you have. We can probably tell you if we know your engine and trans. :thumbsup:

 

 

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most likely, but never assume anything with Jeeps.....

 

if there's not a tag on one of the cover bolts, check the front diff for a tag (assuming you're 4WD). Failing that, the tooth count of the ring and pinion is stamped into the ring gear along the outer face. Locate and divide them to identify the ratio.

 

Jeff

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ok, so i looked, and its a dana 35, but i havnt gotten under her yet so i don't know the gears. now this may sound realy dumb, but lets say I go to the pull and save yard and find another comanche with a dana 35 but a differant gear ratio, could i not use it anyways? or does it have to be an exact match?

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It'll bolt right in. Regardless of the gear ratio, the housings are the same. And if it's from an MJ, the perches will be in the same place, so it will be a direct swap.

 

Is it 4wd? If it is, you'll need the same ratio, unless you swap the front to match. And don't forget speedo gear if you change ratio.

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If you have a 2.5L, then you do not want to go with a higher ratio (numerically lower). Your truck will feel like it's suddenly hauling around 500 pounds in the bed everywhere you go. :ack: And if it's 4wd, then you absolutely must match the front axle is you ever want to use 4wd (breakage will occur).

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Hey all, well, on the way home yesterday, I had a loud noise and some "thunking" come from the rear dif, then the driveshaft ripped from the ubolt!!! :mad: so now I'm needin a new rear end, gonna go to the junk yard, so how do i find out what rear end I have? how many did they make for these old jeeps? ( just bought it a week ago so I know nothing about it) thanks

 

Do you know for sure the rear end is bad? You may have snapped a ujoint and just need to replace the yoke on axle. If so thats a quick easy fix.

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Do you know for sure the rear end is bad? You may have snapped a ujoint and just need to replace the yoke on axle. If so thats a quick easy fix.

 

Well, here's what happened, after the initial " thunking" sound, it then sounded like there where rocks in the diff, a rattling sound as i drove, after I pulled over, I then noticed I no longer had reverse. So I turned around and went back home but on the way, on top of the " rattle sound, it then started making a "whirling" from the diff that got louder and louder, and then snap, the drive shaft broke. so we tied the drive shaft up tp the frame and towed it home, but while being towed, it was still making the rattling sound from the diff.

 

Since getting it home, i got under it today, ( only briefly though) , pulled off the diff cover and the diff oil is a pitch black tar. so i can't even see the gears through that muck. how would you recomend cleaning it all off? and is it worth it to look into repairing this axle, or should I just start searching the junk yards for a new one?

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to clean out all the diff oil use brake cleaner. go buy a can or two and just spray it in there and itll start getting clearer and clearer. i think it would probably be easier to just swap the axles instead of rebuilding the axle. but if you get a different one then you could risk the chance of your jeep driving like crap like pete said above.

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