Knucklehead97 Posted July 18, 2016 Share Posted July 18, 2016 So I change my mind quite often. Initially when I heard the rear axle in my auto MJ start to go out I was thinking "oh! I'll go ahead and drop the cash on a 4.10 geared 8.8 and new 31's!". Well I have A LOT of things I need to spend my money on before that. But my axle is leaking a bunch and I want to get the axle handled somehow. So what have I decided to do? Build the axle for my stickshift MJ which has a blown transmission! I want to run 31's on both and want 3.55's in the stickshift one. So since I have brand new 235's on my auto MJ and want a simple axle swap I am going to go ahead and build the 3.55 axle for the stickshift one but run it under my auto one till I wear my tires down and get ready to build the 4.10 geared 8.8. Get what I'm saying? Now down to business... is the Cherokee 8.25 easier to swap in than the 8.8? What all do I have to do? Which year Cherokee should I find one out of? HOW can I tell that the axle is good without driving the Jeep first? I'm guessing that I will just need new spring perches. Can I use my old shock mounts that are held by the Ubolts or will I have to figure out another option? If I decided to go ahead and throw on disk brakes what is EVERYTHING I will have to do? Already have a WJ booster to swap in, how would I go about the Proportioning valve and the rear axle valve (forgot what it's called.) Will I have to do anything involving the driveshaft or should the length still be right? Bunch of questions. But as always, thanks a bunch. Link to comment Share on other sites More sharing options...
SBpunk Posted July 18, 2016 Share Posted July 18, 2016 Its cheaper thats for sure. You have less options for lockers down the road, think the gearing caps out at 4.88, look for a 94+ for the 29 spline out of an auto and still trying to figure out the u bolts and shock mounts.If you're doing spring over go with the longer spring perches (ruffstuff is a good company) under it doesn't really matter. Grab a 96 XJ brake booster. Its damn near bolt in depending on what year you're working with. Even if its not its a lot less work. Disk brakes and prop valve I haven't looked into yet Link to comment Share on other sites More sharing options...
fire797 Posted July 18, 2016 Share Posted July 18, 2016 you should read the pinned stuff in the DIY section.... there is lots of info in there on all these questions.... Link to comment Share on other sites More sharing options...
sloride Posted July 18, 2016 Share Posted July 18, 2016 I did the 8.25 swap with the '94zj disc brake swap. With exception of enlarging the backing plate with a sanding drum, the disc swap was easy. Had to do the longer wheel studs as well. The load sensing valve I swapped with an adjustable prop valve. Link to comment Share on other sites More sharing options...
Eagle Posted July 18, 2016 Share Posted July 18, 2016 The 8.25 swap is VERY easy, and much less expensive than an 8.8 swap. If you just need to put it in and drive, all you need to do is move the spring perches. The axle is already the correct width, so you don't need any spacers, or wheels with different backspacing. The pinion yoke is the same as for an MJ, so you don't need an adapter flange. You should be able to cut off the original spring perches and weld them back on in the correct place for the MJ installation. You can obviously use the original MJ shock mounts, since they aren't part of the axle. You can either leave the XJ shock mounts on the axle tubes, or cut them off -- your option. While you can do a disc brake conversion, it's not necessary if you just need an axle to drive on. The rear brakes in an MJ when not running loaded do even less work than the rear brakes in an XJ, so IMHO there's not much to be gained by doing the disc brake conversion. The 8.25 pinion is about 1-inch longer than the D35, so unless you're doing a lift at the same time you will also need to shorten the drive shaft by an inch. (You would also have to do this with the 8.8.) Link to comment Share on other sites More sharing options...
88whitemanche Posted July 18, 2016 Share Posted July 18, 2016 97+ Cherokees had the 29 spline axle shafts(bigger axles) as the 96- had the 27 spline (some will say the same strength/size of a Dana 35).... Link to comment Share on other sites More sharing options...
SBpunk Posted July 18, 2016 Share Posted July 18, 2016 97+ Cherokees had the 29 spline axle shafts(bigger axles) as the 96- had the 27 spline (some will say the same strength/size of a Dana 35).... Thats right. Was thinking of the U joints on the dana 30 fronts Link to comment Share on other sites More sharing options...
Knucklehead97 Posted July 18, 2016 Author Share Posted July 18, 2016 Won't be lifting it more than 2" if at all anytime soon so I guess I have got to find someone to shorten the shaft. 97+ it is! Not sure if I'll do the disks before or after. Chances are since I'm lazy I'll do them after. Is the pumpkin centered on the axle of the 8.25? On the 8.8 I was told it wasn't so you have to measure from somewhere else to set the perches up. I found pairs of mopar spring perches on Amazon for 18$ shipped so I will probably order some of those instead of keeping the old ones after removing. I'm guessing to make sure the axle is good I should just check it for leaks and pull the cover to see how clean it is/if anything is tore up inside? Link to comment Share on other sites More sharing options...
SBpunk Posted July 18, 2016 Share Posted July 18, 2016 Good time to do it. I stripped mine all the way down. Its prepped for sandblasting but I pulled the seals, out side bearings, brakes, shafts and anything else including the carrier to get it ready. I'd weld the perches on with the shafts out for sure. Link to comment Share on other sites More sharing options...
Knucklehead97 Posted July 19, 2016 Author Share Posted July 19, 2016 If the seals look worn chances are I will pull the carrier and change the axle seals and bearings. Only seal I don't feel comfortable changing is the yoke seal (like is leaking on my 35... of course.) Paint job will most likely happen before I install. I like pretty things haha. Link to comment Share on other sites More sharing options...
SBpunk Posted July 19, 2016 Share Posted July 19, 2016 Same here. Heard you have to reset the gears when you change out the rear yoke seals. I wish I had the skills to do it would save me a lot of money down the line when I step up to 4.56 gearing. Link to comment Share on other sites More sharing options...
DirtyComanche Posted July 19, 2016 Share Posted July 19, 2016 Same here. Heard you have to reset the gears when you change out the rear yoke seals. I wish I had the skills to do it would save me a lot of money down the line when I step up to 4.56 gearing. Just don't smash the crush sleeve any tighter when you torque the pinion nut and it will be fine. Normally the crush sleeve needs a fairly ridiculous amount of torque to crush, so you can put locktite on the threads and torque the nut to a 'safe' number, stake it, and it won't change a thing. You can also put a witness mark between the nut and pinion before you take it apart, thus you can see if you're going to tighten it too much. Link to comment Share on other sites More sharing options...
Knucklehead97 Posted July 19, 2016 Author Share Posted July 19, 2016 I'll learn how to set the gears eventually, or learn the easy way like he's talking about haha. My plan on setting the pinion angle/perch width is to measure the differential housing, subtract it's width from 42", half it, and set them the halved distance from the housing. Then also measure the full axle width, subtract 42" from it, half it, and see if that measures out to place them in the same spot as the other measurements. The angle I will find from checking the angle on the current axles yoke and then setting the yokes degree to that while the perches are 100% level. Kind of confusing to explain. Link to comment Share on other sites More sharing options...
75sv1 Posted July 20, 2016 Share Posted July 20, 2016 Same here. Heard you have to reset the gears when you change out the rear yoke seals. I wish I had the skills to do it would save me a lot of money down the line when I step up to 4.56 gearing. Just don't smash the crush sleeve any tighter when you torque the pinion nut and it will be fine. Normally the crush sleeve needs a fairly ridiculous amount of torque to crush, so you can put locktite on the threads and torque the nut to a 'safe' number, stake it, and it won't change a thing. You can also put a witness mark between the nut and pinion before you take it apart, thus you can see if you're going to tighten it too much. I think you mark the nut and flange. Count the rotations to take the nut off. Then assemble the nut with the counted rotations (turns). Then about a 1/16 turn more. The correct way is you need an inch-lb torque meter. If assembled, then rotate the nut with the torque meter (dial type). Get that reading. Need to torque the nut when reassembled to that torque value. Can use a new nut and sleeve. At least that is what I am told. Link to comment Share on other sites More sharing options...
SBpunk Posted July 20, 2016 Share Posted July 20, 2016 I'll learn how to set the gears eventually, or learn the easy way like he's talking about haha. My plan on setting the pinion angle/perch width is to measure the differential housing, subtract it's width from 42", half it, and set them the halved distance from the housing. Then also measure the full axle width, subtract 42" from it, half it, and see if that measures out to place them in the same spot as the other measurements. The angle I will find from checking the angle on the current axles yoke and then setting the yokes degree to that while the perches are 100% level. Kind of confusing to explain. Sounds better than my plan. Was just going to measure the distance between the outside of the spring perches on the old axle and mark the center. Then get the center on the new axle from measuring tube end to tube end. From that center mark the distance out from the old axle on the new Link to comment Share on other sites More sharing options...
DirtyComanche Posted July 20, 2016 Share Posted July 20, 2016 Same here. Heard you have to reset the gears when you change out the rear yoke seals. I wish I had the skills to do it would save me a lot of money down the line when I step up to 4.56 gearing. Just don't smash the crush sleeve any tighter when you torque the pinion nut and it will be fine. Normally the crush sleeve needs a fairly ridiculous amount of torque to crush, so you can put locktite on the threads and torque the nut to a 'safe' number, stake it, and it won't change a thing. You can also put a witness mark between the nut and pinion before you take it apart, thus you can see if you're going to tighten it too much. I think you mark the nut and flange. Count the rotations to take the nut off. Then assemble the nut with the counted rotations (turns). Then about a 1/16 turn more. The correct way is you need an inch-lb torque meter. If assembled, then rotate the nut with the torque meter (dial type). Get that reading. Need to torque the nut when reassembled to that torque value. Can use a new nut and sleeve. At least that is what I am told. Counting turns sounds good and everything, but I take that sort of stuff apart with the impact and it's extremely hard to tell. The nut will torque up nearly where it was before, and as long as you do not exceed the torque needed to crush the sleeve (probably about 200ft-lbs) you will not affect the bearing preload. But yes, if you're using hand tools and want to count turns, go right ahead, it will work fine. Be careful going past the marked line, as if it was torqued quite tight prior that 1/16 turn may be enough to crush the sleeve a bit, although it is not likely. Also you can't/shouldn't mark the nut against the flange/yoke, as the flange/yoke is not master splined and can be put on the pinion in many different orientations. Standard practice when pulling a flange/yoke is to mark it against the pinion (or whatever splined shaft it is on) so it can be reassembled the same way, so really one should just draw a nice line with the paint pen across the pinion, nut and yoke, or center punch each of them in line. Otherwise, yes, pull the carrier, measure drag torque (preload) with a dial torquewrench/torquemeter, take the nut/yoke off, install new crush sleeve, install seal, reassemble, torque until the prior measured drag torque is achieved. Waste of time. Link to comment Share on other sites More sharing options...
Knucklehead97 Posted July 28, 2016 Author Share Posted July 28, 2016 http://www.speedwaymotors.com/Speedway-Leaf-Spring-U-Bolt-10-Inch-Long,2154.htmlwill these work for U-bolts or should I look elsewhere? Fixing to start ordering parts and finding an axle in the next couple weeks. Link to comment Share on other sites More sharing options...
Knucklehead97 Posted July 28, 2016 Author Share Posted July 28, 2016 Also what is a good price for an 8.25? Got a guy selling one out of an 98 sport for 200$. Says it doesn't roar and has no leaks. Waiting to get pictures. Link to comment Share on other sites More sharing options...
DirtyComanche Posted July 28, 2016 Share Posted July 28, 2016 $100-200 is pretty normal for a price. Link to comment Share on other sites More sharing options...
Rockfrog Posted July 28, 2016 Share Posted July 28, 2016 Sold mine recently for $200cdn along with a gutted D30 with carrier/gears still in. Common price around here is $100-150cdn for a good 29spl 8.25 axle. Sent from my SGH-I337M using Tapatalk Link to comment Share on other sites More sharing options...
Knucklehead97 Posted July 28, 2016 Author Share Posted July 28, 2016 If all is actually good with this one I'll probably jump on it simply because it saves me from having to run to junkyards and pull multiple covers off. My local junkyard wants 150$ an axle anyways so it wouldn't be much of a difference. Link to comment Share on other sites More sharing options...
Knucklehead97 Posted July 30, 2016 Author Share Posted July 30, 2016 Guy said he bought the Jeep to use the front end in his MJ. Drove it home and the rear end had no sounds. He sent me pictures, doesn't seem to have a leak anywhere. I'm going to look at it Sunday. He said he may go ahead and pull it for me tomorrow if he gets bored. I also ordered the spring perches. Haven't decided on U-bolts yet. Link to comment Share on other sites More sharing options...
DirtyComanche Posted July 30, 2016 Share Posted July 30, 2016 You can get u-bolts made locally, often not for a lot of money. Check out a spring shop. I just use 5/8" ones for everything, better too strong than not strong enough. Link to comment Share on other sites More sharing options...
Knucklehead97 Posted July 30, 2016 Author Share Posted July 30, 2016 You can get u-bolts made locally, often not for a lot of money. Check out a spring shop. I just use 5/8" ones for everything, better too strong than not strong enough. I've been searching for driveshaft shops and spring shops around here to get quotes from but I don't think there are any haha. I've got to ask around a bit. Link to comment Share on other sites More sharing options...
DirtyComanche Posted July 30, 2016 Share Posted July 30, 2016 Or just buy these: http://www.ruffstuffspecialties.com/catalog/UB3.html Link to comment Share on other sites More sharing options...
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