HatchetMJ Posted October 3, 2005 Share Posted October 3, 2005 Alright I bought a donor XJ with a 6cylinder, 242 and AW4 to put into my MJ and make it 4wd from 2wd. I got to looking at it and find that the MJ rear axle is sprung under while the XJ rear axle is sprung over. Is there any reason why I can't take the axle and leafs out of the XJ and just mount it into my MJ already sprung over. This would allow me to just purchase a lift for an XJ in the future. Instead of an add a leaf setup...then I'd be able to get full spring packs. Do the leafs measure the same from center to center of the mounting bolts? The front axle is an easy swap...I would just leave what I have in the rear alone...but I want to make sure the gears are the same in both axles because I can't read them since the tags have rusted off and have really no way of knowing what they are...at least by swapping in that rear I know it will match the front. Link to comment Share on other sites More sharing options...
Pete M Posted October 3, 2005 Share Posted October 3, 2005 What year XJ? The XJ and MJ have different distances between the pads, so welding new pads on is required. Leafs are very different too. The MJ has longer ones and a ton more arch in them. Taking your current SUA setup and going SOA will net 5-6 inches of lift. The vast majority of 4.0L/auto Jeeps have 3.54 gears, but the only way to know for sure which gears you have is to pull the covers off and read what's stamped on the ring gear. It's a great opportunity to put fresh fluid in and check the overall condition of the axle. Jeep on! --Pete Link to comment Share on other sites More sharing options...
HatchetMJ Posted October 3, 2005 Author Share Posted October 3, 2005 What year XJ?The XJ and MJ have different distances between the pads, so welding new pads on is required. Leafs are very different too. The MJ has longer ones and a ton more arch in them. Taking your current SUA setup and going SOA will net 5-6 inches of lift. The vast majority of 4.0L/auto Jeeps have 3.54 gears, but the only way to know for sure which gears you have is to pull the covers off and read what's stamped on the ring gear. It's a great opportunity to put fresh fluid in and check the overall condition of the axle. Jeep on! --Pete its a 91 XJ...the MJ is an 89....and I figured it wouldn't be as easy as just swaping it out....guess I'll be breaking out the welder :D Link to comment Share on other sites More sharing options...
Pete M Posted October 3, 2005 Share Posted October 3, 2005 Are you swapping in the h.o. 4.0l too? Link to comment Share on other sites More sharing options...
HatchetMJ Posted October 3, 2005 Author Share Posted October 3, 2005 Are you swapping in the h.o. 4.0l too? yep...I'm swapping in the entire drivetrain.. :D 2.5L 4spd manual just wasn't gonna cut it..lol so it will now have 4.0L 242 and auto tranny Link to comment Share on other sites More sharing options...
Pete M Posted October 3, 2005 Share Posted October 3, 2005 Your current rear axle should have 4.10 gears (again, the only way to know for sure is to check) which is better for bigger tires. Personally, I would sell the XJ axles off (maybe to someone looking to upgrade the lousy 3.07 gears in their 4.0L/manual) and buy another 4 banger front axle to get 4.10 gears. Or you could regear. It all depends on what you want in the end. Jeep on! --Pete Link to comment Share on other sites More sharing options...
HatchetMJ Posted October 3, 2005 Author Share Posted October 3, 2005 Your current rear axle should have 4.10 gears (again, the only way to know for sure is to check) which is better for bigger tires. Personally, I would sell the XJ axles off (maybe to someone looking to upgrade the lousy 3.07 gears in their 4.0L/manual) and buy another 4 banger front axle to get 4.10 gears. Or you could regear. It all depends on what you want in the end. Jeep on! --Pete that being the case I'll probably just regear the front axle to what my rear has and call it good...after i get the drivetrain in...I can always change the axle...thats easy enough to do.... Link to comment Share on other sites More sharing options...
pingpong Posted October 4, 2005 Share Posted October 4, 2005 The myth out there that all Xj's with a 4 banger have 4.10's is false. Some came with 3.73's, so check first. As for just swapping the entire drivetrain over... It isnt that easy. the 4cyl has a different wiring harness then the 4,0. Also you wil have to change the frame mounts and a few other things. If you are going to go through the trouble of swapping rear axles, and doing the welding and what not... I recommend swapping in an axle that is stronger then the D35. I swapped 2 in before I swapped an 8.8 in. Patrick Link to comment Share on other sites More sharing options...
88emjay Posted October 4, 2005 Share Posted October 4, 2005 About the 4.10's in 4 bangers myth... About a year ago I bought an 86 XJ 4cyl 5spd as a parts jeep. It had 3.54 gears in it, and I still have that front axle now in my MJ. I guess the 4 bangers were available with everything but 3.07's. 88Emjay Link to comment Share on other sites More sharing options...
HatchetMJ Posted October 4, 2005 Author Share Posted October 4, 2005 The myth out there that all Xj's with a 4 banger have 4.10's is false. Some came with 3.73's, so check first. As for just swapping the entire drivetrain over... It isnt that easy. the 4cyl has a different wiring harness then the 4,0. Also you wil have to change the frame mounts and a few other things. If you are going to go through the trouble of swapping rear axles, and doing the welding and what not... I recommend swapping in an axle that is stronger then the D35. I swapped 2 in before I swapped an 8.8 in. Patrick I aware that the wiring harness is different...I'll be changing that over too as I bought the whole xj with everything intact...I'm also switching out the dash too.. I will eventually swap in a stronger axle...but for now I just need to get something in there so I can get it moving again...eventually I plan to go full width and put a dana 60 in the front and a 14 bolt in the rear Link to comment Share on other sites More sharing options...
Bounty Hunter Posted October 4, 2005 Share Posted October 4, 2005 About the 4.10's in 4 bangers myth...About a year ago I bought an 86 XJ 4cyl 5spd as a parts jeep. It had 3.54 gears in it, and I still have that front axle now in my MJ. I guess the 4 bangers were available with everything but 3.07's. 88Emjay Most common in 4bangers are 3.73 (auto tranny) and 4.11 (manual tranny). Your 3.55 is the first I've heard of, and there are reports of rare 4.56 available as well. Like anything else Jeep, just when you think there is a steadfast rule, it isn't. Link to comment Share on other sites More sharing options...
pingpong Posted October 4, 2005 Share Posted October 4, 2005 According to some Jeep "experts" 4.56's were available with the 2.8 if equipped with some special options. I think this was the 2.8's version of a tow package gearing. Not sure what rear axle it came with, but due to the yr, I am going to assume it was the D35 non c-clip. Patrick Link to comment Share on other sites More sharing options...
mjeff87 Posted October 4, 2005 Share Posted October 4, 2005 According to some Jeep "experts" 4.56's were available with the 2.8 if equipped with some special options. I think this was the 2.8's version of a tow package gearing. Not sure what rear axle it came with, but due to the yr, I am going to assume it was the D35 non c-clip. Patrick I just scored a 4.56 D30 last weekend. It came from an 87 XJ w/ 2.5L and AW4. About as rare as they come... I also possess a 3.73 '30 that came from an 87 MJ with 2.8 w/ auto trans that have 3.73's. It, however, is going back to the junkyard next week so I can get my $25 back on the core deposit for the 4.56 one (unless someone needs it??) Jeff Link to comment Share on other sites More sharing options...
pingpong Posted October 5, 2005 Share Posted October 5, 2005 Pull the gears and carrier out of it. I have severeal sets of 3.07 and 3.55's that I was going to turn into modern art and weld them all together along with broken axles and other parts. 3.73 and 30 or 31's is a perfect cobo for any newbies out there. Patrick Link to comment Share on other sites More sharing options...
comancheon33 Posted October 6, 2005 Share Posted October 6, 2005 I parted out an 86 MJ 2.8 auto 4x4 two years ago that had 4.10s in it. I sold to friend that has them in his XJ still. Link to comment Share on other sites More sharing options...
DirtyComanche Posted October 6, 2005 Share Posted October 6, 2005 Know what's funny... There's no such thing as a 4cyl cherokee in Canada... I've never seen one, and only one yard of all the ones I go to has ever 'processed' one. That killed my cheap regearing plan fast. Link to comment Share on other sites More sharing options...
Eagle Posted October 12, 2005 Share Posted October 12, 2005 By way of confirmation, my '88 2.5L 4-speed MJ has 3.54 gears. They used the taller gearing to compensate for the lack of an overdrive 5th gear. And ALL 4.0L automatic XJs came with 3.54 gears -- contrary to popular misconception, in the 4.0L years there was never an optional "tow package" axle ratio. There's a very good chance that the front axle from the XJ already matches the MJ rear axle and no changes will be necessary to make it 4WD. Link to comment Share on other sites More sharing options...
pingpong Posted October 12, 2005 Share Posted October 12, 2005 Eagle, I hate to rain on your parade.... The ratio for auto equipped Xj's with the 4.0 is 3.55, with an optional 3.73 if you did get the factory towing package. If you have the 5spd xj with 4.0 you have 3.07 gears. Patrick Link to comment Share on other sites More sharing options...
Bounty Hunter Posted October 12, 2005 Share Posted October 12, 2005 PingPong, you're not raining, our '98 XJ with tow package and auto had 3.55 gears, never seen the 3.73 with the 4.0L auto tow setup. Eagle, nice to see you here. Link to comment Share on other sites More sharing options...
Pete M Posted October 12, 2005 Share Posted October 12, 2005 For what it's worth (cause they don't exactly tell if it had a tow package or not) car-part.com has a listing for a Dana 35 with 3.73 gears and ABS. There are only 2 pages of listings (and some of those listings aren't even 3.73, cause junkyard guys aren't apparently all that computer-savy) as compared to 150+ pages of 3.55 geared axles. Jeep on! --Pete Welcome aboard Eagle!! :D Link to comment Share on other sites More sharing options...
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