I'm hopeing some will know the axle codes for jeep's and cherokee's.I've been researching a lift kit and 31" tires for a cherokee but I dont want to do that if the gearing isnt going to be correct.I have put bigger tires on truck's before and because of the bearing it just killed it in the power area.Thank's

Don't know about axle codes but the front is going to almost always be a Dana 30. The rear will be a Dana 35C or a Dana 44. You can tell them apart by the grease plug. A D35 has a rubber plug and is oval shaped. A D44 has a threaded steel plug and is roughly octagonal. Some earlier Wagoneers had D44 fronts and AMC 20 rears. You might check Reider Racing's website for ID's by year and model. Generally you won't have a problem front or back with 31s on a sheep UNLESS YOU LOCK a D35. then you're asking for trouble. If you're going to lift your sheep and wheel hard, then you need to look into axle upgrades if you have a D35 in the rear. First find out what ya got though.

Baaaaaa

Well thank you nissan-okie I really appreciate it.How can I tell the actually gearing though as far as the ratio and if 31"s are going to kill the power.I do want to lift it but the hardest wheeling we do is climbing the sand dunes and playing in the mud.There arent any rocks here in michigan to climb.So I would'nt really know what hard wheeling would be considered or if changing the axles is really necessary..Thanks again

Well I find out this and thought I would share just in case anyone needed to know.
3.07-Were used with the 4.0 engine with a manual trans.
3.31-available only on pre87 w/the fuel economy package
3.55common with the 4.0 engine and automatic trans.
3.73-common in xj's(cherokee's)w/towing package
4.10-mostly with 2.5 engine,and older xj's w/the "off highway package"
4.56- pretty much a myth unless it's aftermarket

Rubicons have 4.10s
TJs with D44 and automatic usually have 3.73
You're right about 4.56--that's strictly aftermarket