YJ Axles

i picked up some comlete yj axles, driveshafts and steering box/ linkages for $100 this weekend. its a d30 and a d35. i know the 35 is junk but its for my dd comanche with 31's (which currently has a d35). the axles have 4:10 gears so i was hoping that in addition to having spare shafts (they are compatible right? the fronts looked a bit different but they are both CAD axles) i would like to swap the gears. i know its not recomended to swap used gears so what are my other options? i think the rear axle may bolt up since both are SUA but what about the front? it would be a lot of fabbing to swap it in... is the main issue with swapping used gears just the noise? i could live with that...

The front you will have to get coil buckets, control arm brackets and track bar bracket. Rear will not bolt up, so youll need perches and shock mounts.


Its not worth it to swap the D30 and 35 into your MJ. Take the shafts, hubs and brakes as spares, and scrap the rest.

If the gears are not pitted, look worn, or chipped they should be fine. You are aware that you cant just swap the gears over, they need to be set up.

Measure the backlash of the YJ axle's gears before you pull them. When you reset them in the other axle, shoot for the same backlash, and as long as your other settings are right, you should have no problems.

Also, you'll need to swap the carriers out if you have gearing higher (numerically lower) than 3.73 in your current axle. Use the original shims from the axle you're swapping the gears into, and that should get you in the ballpark fairly quickly. It's not rocket science, it just takes time, patience, & attention to detail.

yeah i'm aware of all of the above... but are the rear perches not the same distance apart? i'm guessing thats the issue. but spring perches and shock mounts are a big deal at all. but i agree, i don't think it's worth it to cut and fab all the bracketry for the front. thats why i asked about "swapping" which i'm fully aware is easier said then done and requires a fair amlunt of work. i was just thinking of ripping the guts out of the donors and putting them into the mj axles. obviously they'd have to be set up, just wondering if there was any reason not too. when i did 4.56's in my xj i researched it alot and read some stuff about swapping complete junkyard axles instead of gears because once the gears wear in, they are going to be difficult to set up in a new axle...
BTW anyone know about shaft compatability? the front YJ yokes look more "square" and possibly a bit beefier. they definitely aren't the same but i'm assuming they're still compatible?
Thanks

I cant say about the rear spring perches. The front shafts and everything should be compatable. The front R & P shouldnt be any problem to set up. I know most people advise not to use used gears but YJs have the disco so the R&P isnt turning most of the time and when it does, it doesnt have any torque on it (except in 4WD) so practically speaking, they should have little to no wear on them and of course they are Dana gears which are very good quality to begin with so I think they should set up and run out fine.