chopper56 Posted April 19, 2007 Share Posted April 19, 2007 just blew r.end in one of my manches.its an 87 4x4 w/4.0 ;5 speed.trying to find ratio{spider exploded/locked up ring gear and blew hole in case}can't find any tag anywhere.found ring gear numbers but can't find case stamp.{going to put in whole/hub to hub}know where they are supposed to be?scraped/brushed a lot of rust/oil and no luck.getting different numbers/ratios/location of numbers from everyone .here's my ring#050687dana042717b3r1424013{does this mean dana42 w/307 gears?its a 10 bolt w/oval case}one guy called;said he thinks one hes got will work;got stamp on case reads 42518.huh??!!can someone clear me up on this before i lay cash down on wrong rear?thanks in advance.{new user} Link to comment Share on other sites More sharing options...
Pete M Posted April 19, 2007 Share Posted April 19, 2007 With a 4.0L and manual transmission, you should have 3.07 gears and the rear axle is a Dana 35. If you're riding on tires bigger than stock, now is a good time to think about getting axles with a better ratio. 3.55 is a very common ratio in Cherokees and you just need to weld new leaf mounts on them to work in a stock MJ. try car-part.com for junkyard searching. If you're running tires bigger than 31s, nows the time to think about buying a stronger rear axle too. Don't pay more than $200 for a Dana35 and that's if it is in perfect working order. Most of us can find them for $100 or so. And sometimes for free. :brows: Link to comment Share on other sites More sharing options...
mjeff87 Posted April 19, 2007 Share Posted April 19, 2007 Keep spinning the ring gear around and look for a set of two numbers all by themselves. Those will be the tooth count of the ring and pinion, and will look something like this: 41 10 (for 4.10's) 37 9 (for 4.11's) etc..... Jeff Link to comment Share on other sites More sharing options...
chopper56 Posted April 19, 2007 Author Share Posted April 19, 2007 appreciate the swift replies.yeah;got a 3"lift w/overloads in rear and running 31"rs.with the amount of damage to 3rd member didnt pull axles to get ring n assembly out {was just going to put whole r.e.in}ring gear is jammed/locked in tight.can't rotate.like i said,ive got a couple guys with whole units to sell me{for under a buck n 1/4;thanks for the heads up pete}but don't i need to keep the same ratio{compatability to the fronts?}guess ill just have to pull axles/check ring for more #s then see if I'm close to what the 42518 r.end he has comes out to .thanks again guys.good thing ive got a day off! Link to comment Share on other sites More sharing options...
Pete M Posted April 19, 2007 Share Posted April 19, 2007 Yes, the front must match the rear. But if you're going to spend money replacing the rear anyways, now is the time to consider buying a pair of axles with better gear ratios. I would. Heck, I did! My newest MJ is getting a pair of 3.55 axles and I didn't even blow up the previous set yet. I hate 3.07 gears that much. I'm not even going to sell the old axles. I'm using them as guinea pigs for a practice tear-down, then I'm going to set aside the guts (as wheeling spares for other people) and then haul the carcasses off to scrap. Link to comment Share on other sites More sharing options...
mjcanoe Posted April 19, 2007 Share Posted April 19, 2007 chopper56, You can check frt. diff. for tag. If that is not there use this formula straight from OEM manual, count the ring/pinion tooth combination: 2.73:1 will have 41 teeth on ring gear, 15 teeth on pinion gear. 3.07:1 = 43/14 3.31:1 = 43/13 3.55:1 = 39/11 3.73:1 = 41/11 4.11:1 = 37/9 They did run 4.10/ 4.11 together as the difference was allowable, I have this combo in my mj & it is oem. hope this helps. mjcanoe Link to comment Share on other sites More sharing options...
chopper56 Posted April 19, 2007 Author Share Posted April 19, 2007 yeah,front tag is almost readable lol; [scrape,clean,do it again /wire brush...u guys know}got a #set of 7181 or 7131.noone around here has a clue.my dealer buddies only have books ect. that go back to 93 or so.gonna do more checkin.i know cherokee rears won't work without fabs so hopin to find something.thanx again guys;knew this site was worth gettin to.{my mistake...some cherokee rears are interch.going to do some more measuring.}thanx again! Link to comment Share on other sites More sharing options...
Pete M Posted April 19, 2007 Share Posted April 19, 2007 It's really very easy to use a Cherokee rear axle. All you need to do is get new perches welded on. I recommend the Mopar perches rather than trying to reuse stock Jeep ones. Link to comment Share on other sites More sharing options...
mjcanoe Posted April 19, 2007 Share Posted April 19, 2007 chopper56, If not able to read tag on frt.diff., the gear ratio based on tooth count(ring/pinion) will still tell you what you nee to know. I know a lot of folks beef about D35, but outside of 3 sets of spider gears, they never hurt my feelings. Upgrading to @ least 4.10's would be ideal for @ most 32" tires. mjcanoe Link to comment Share on other sites More sharing options...
ifixit8 Posted April 20, 2007 Share Posted April 20, 2007 I just went down this same road. but mine didn't blow up as bad. It should be 3.07 gearing. i just went and got 3.55 axles from a cherokee. I still need to do the front, but it seems the best way to go. good luck finding/figuring it out!! Link to comment Share on other sites More sharing options...
chopper56 Posted April 20, 2007 Author Share Posted April 20, 2007 yeah,thanx guys.found third mem. w/housing{super clean}.I'm going to throw in my axles/drums ect. and see how it works.just need it moving right now.hoping it lines up.measured my perches and seems to be the same according to seller.{hes an old cherokee diehard,his son bought him this rear 4 years ago and never used it}.thanx again for all the info;let you guys know how it turns out. tc Link to comment Share on other sites More sharing options...
speed_racer Posted April 20, 2007 Share Posted April 20, 2007 remember... xj = SOA... mj = SUA.... Link to comment Share on other sites More sharing options...
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