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need help, rear end bad.


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First I just wanted to say Hi :waving: . I just recently bought an 88 mj 4.0 5-speed long bed for $600. the thing was hit in the passenger rear but not to bad. only 80k on the clock and a blown rear end. now the problem i have is figureing out what gear ratio it has. I took the cover off and tried counting the ring & pinion. then my friend also tried counting it. he came up with a gearing of 2.85, now i know that isn't right. I'm thinking it's a 3.07. so the question is, is there any way to tell without taking the whole thing apart? or does anyone know what is the common rear end for the mj's with my setup? the onther issue i'm having is if it's a 44 or 35. any help will be greatly appreciated!!!!! thanks.

 

Devin

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if your going to get a new axle upgrade to any thing other than d35 go with the 8.8 or even the 8.25 or if you can find the d44. Just remeber if it is 4x4 make sure your gears match front and rear. And welcome to the club. I am in centeral IA and i have the 8.8 with 3.73 gears and a MJ D35 w/3.07 4 sale if you would want any of the two let me no. I also have a D35 out of a 91 xj w/3.55 gears.

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A tip for future axle ratio identification, if the tag is missing. The tooth count of both the ring and pinion are stamped into the outer face of the ring gear. Wipe off the surface, and spin the ring around until you see two sets of numbers all by themselves. Divide them to get the ratio.

 

Welcome to the club, BTW :cheers:

 

Jeff

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well I will be picking up a new/used rear end from the local junk yard. the guy at the desk says that it will be a 3.08. I really hope he is right. I had him pull that off another jeep. I think it's an old cherokee. I know that I should upgrade but, i need to get this thing running with the crappy weather we have been having in upper IL. the guy at the junk yard said that it would have the right gearing stamped on the front diff, has anyone else heard of that? if so then i should have just done that. I appreciate all the help and welcomes to the the club. thanks.

 

mjeff87- thanks for the tip I guess i could still confirm it tommorow when i go over to my friends house to work on it. I just was hoping that i didn't have to rip the whole thing apart to find the right gear.

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I had him pull that off another jeep. I think it's an old cherokee.

Wha-oh! Rear axle? Cherokees have the leaf springs over the axle, Comanches have the leaf springs under the axle...

 

lol, i guess he's gonna get some extra lift....

 

man is freerocknok right...you need axles from a comanche if you're trying to get it working in a timely fashion. it's not exactly like ALL parts on the cherokee/comanche are completely interchangeable.

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goto the chryco dealership, order the mopar performance perches. They're $8 for the SET.

Have a buddy weld them on for beer, using your old axle as the template. Takes about 20 minutes with a welder to do it right.

Do we have a part number for these?

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search under eagle's name on naxja, he posted them some time ago. That's what I used when I put an XJ axle under the truck. They're for a 3" radius tube, but a little grinder work took care of that.

Dirt cheap, and beefy, made for the mopar muscle guys.

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search under eagle's name on naxja, he posted them some time ago. That's what I used when I put an XJ axle under the truck. They're for a 3" radius tube, but a little grinder work took care of that.

Dirt cheap, and beefy, made for the mopar muscle guys.

 

thanks for the tip. the guy at the junk yard said "just flip the axle around", i was like what? then he said yeah all the ppl that lower the chevy s10's flip the axle and put the leafs under the axle. i don't think it will work but we'll see tommorow when i get the axle. because of this crappy weather they didn't have any guys available to take the axle off today. but at least I scored some bucket seats from the same 89 xj.

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If you flip the axle, A: Oil will come out and B: You'll have as many reverse gears as you used to have forwards (I found out the hard way when I was a teenager. I wanted to lift my '66 Nova so we flipped it and got 1 speed forwards and 2 reverse (powerglide) The direct cut gear whine was passed off as turbo! LOL!

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That's not gonna work. Even if it did the spring perches would still have to be moved. Your gonna have to either do some welding or find a MJ axle.

 

Thats what i had figured. I'll more than likely either weld or take it apart and put the new gears in the old rear end.

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You can't simply "bolt in" new gears. They need to be "set up" and that takes special tools, knowhow and lots of patience, or money (to have someone else do it, like 100-200 bucks). It is generally something to be avoided. Get the correct gears in your new axle. Getting welding done is easy. :D

Jeep on!

--Pete

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You can't simply "bolt in" new gears. They need to be "set up" and that takes special tools, knowhow and lots of patience, or money (to have someone else do it, like 100-200 bucks). It is generally something to be avoided. Get the correct gears in your new axle. Getting welding done is easy. :D

Jeep on!

--Pete

 

So welding it is!! that's not to hard of a thing to do anyways. I have done some welding myself and I also have 2 friends that could do it. one will be helping me with the swap anyways so it will more than likely be him.

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You can't simply "bolt in" new gears. They need to be "set up" and that takes special tools, knowhow and lots of patience, or money (to have someone else do it, like 100-200 bucks). It is generally something to be avoided. Get the correct gears in your new axle. Getting welding done is easy. :D

Jeep on!

--Pete

 

So welding it is!! that's not to hard of a thing to do anyways. I have done some welding myself and I also have 2 friends that could do it. one will be helping me with the swap anyways so it will more than likely be him.

Shouldn't be a problem then! Everything else should be good, just get those perches moved. They also don't line up with the Cherokee perches. They need to be moved to the inside something like 3/4" on each side, so measure your old axle.

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when I did mine it went like this:

 

Take out old axle.

Remove axleshafts

Measure perch distance from flange on axle tube

Tak off diff cover, plumb the gasket surface.

Measure perch angle with an angle finder.

 

Take measurements and angles to new axle.

Plumb up the gasket surface, set perches in place at proper angle.

Weld them on.

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