i took my 87 4runner on the road to see if i had the exhaust problem fixed and before i put my brakes on something in the rear end of my rig was making a crazy sound.  when i got home to look at it there was fluid all over my rear axle and all over the tail gate.  Does anyone have a clue what the noise is and how to fix the problem??????    

Where is the oil coming from? Sounds like it could be the pinion seal or even the rear output shaft seal on the t-case.

What kind of noise was it? Screeching? Metal on metal? High pitch? Banging? Clanking? Does it change as the speed changes? Constant?  

Sounds to me like the pinion bearings are gone and pinion seal with it.  

Clean all the fluid off.
Put the rear axle on jack stands.
Check the gear oil level off the diff (plug halfway up on the back).
If it's low you know the source of the leak.
Rotate the wheel by hand to see if you can locate the source of the noise - diff, u-joint, wheel, t-case, brakes, etc.
If the noise seems to be coming from the diff you might want to grab the u-joint and see if there's any side to side or in and out play (not rotational play).
Report back with the results.