need help, rear end bad.

[ifixit8]

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

[RandysMJ]

4.0 and 5spd will have 3.07 gears.

 

Dana 35

 

Dana 44

[ifixit8]

4.0 and 5spd will have 3.07 gears.

 

Dana 35

 

Dana 44

 

Thanks for the help!!! yeah it's the 35. now I just got to find new gears or a whole new rear end.

[feerocknok]

If it's a 2wd, it'll be a little easier to find an axle for as 3.55s should be acceptable as well, and you won't have to match your front end.

[Rokhound]

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.

[mjeff87]

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

[Pete M]

Whatever you do, don't try to fix a Dana 35. It's simply not worth it when a complete axle can be had for very little (and with better gearing).

[ifixit8]

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.

[DirtyComanche]

It's a 3.07~ (3.08, w/e) - unless it isn't stock.

 

 

 

A 4.0 and a 5spd ALWAYS got 3.07s.

[ifixit8]

It's a 3.07~ (3.08, w/e) - unless it isn't stock.

 

 

 

A 4.0 and a 5spd ALWAYS got 3.07s.

 

 

(3.08, w/e) sorry, but what exacly does that mean? I must be having a stupid moment. thanks.

[feerocknok]

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...

[JeepcoMJ]

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.

[87manche]

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.

[feerocknok]

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?

[87manche]

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.

[feerocknok]

go to any Mopar dealer and order up one unit of part number P4120074. Should cost you about 12 bucks, and what you will get is a PAIR of extremely heavy duty spring perches.

 

Voila!

[87manche]

yep, that was the tip of the century when I bought them. Cheap and beefy.

The centering hole is a little bit big, so make sure you get a new centering pin that fits snugly. I used the calssic cap head allen screw.

[ifixit8]

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.

[RandysMJ]

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.

[carnuck]

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!

[ifixit8]

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.

[Pete M]

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

[ifixit8]

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.

[feerocknok]

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.

[87manche]

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.