vaccum help(i think)

ok so im still not 100% bout some things xj related, there is/was a hose going from the top of my front axle to i think the intake. is this a vaccum disco? and if so what happends when that hose gets ripped in half? casue it sure has been ripped since the first flex i did when it caught on the drive shaft about 2 years ago, i just been readin alot bout vaccum disco d30's and started thinkin "hey i think thats what i got, wonder what could go wrong with it broke"

The hose from the diff housing to the intake is the breather hose. Just go to the parts store and get a couple feet of rubber hose to replace it. You should probably change the oil too. If you have a vacuum disconnect d30, the vacuum lines are on the passanger side buy the upper control arm. If those lines were cut then you front axle would not go into 4wheel drive.

how do i identify the vaccum lines as being vaccum lines? and is this a good axle or is it better to have a non vac disco axle?