z71 ifs help....

ok who can tell me what are the main problems when an ifs front section goes out. ia few of my friends and i were doing a bit of mudding today and while i was i a nasty rut i noticed a kinda loud pop/bang and my front axle stopped spinning!!! :eek: now i was able to drive the truck around and drive it home just fine and the ifs was making no noises at all. i made a couple more trial runs through the mud and still had no front wheel spin. now when i got home i jacked up the truck at all 4 corners and put it in 4 wheel drive and started it up and put it in gear. the front drive shaft would spin but no wheel movement. well at first i removed the selonoid on the axle housing and tried to see if that was bad. well i pressed the front engagement fork in(on the inside of the housing) and it would still not turn the front tires. any one have any ideas as to what may be the problem??? ill be taking apart the front axle tomorrow to se what i broke. oh what fun :disappoin
thanks