My 87 Sami drives up and down the road like a dream on 32" tires. Left turn.. No problem.  Right turn, no matter how slight a turn, if I'm on the gas even a little there is a horrendous knocking sound coming from the front end somewhere. When I straighten up it stops. It can't tell where it's coming from. 

I don't have lockers.  It's lifted about 7". It's not a tire rub on the leafs or anything.  Everything seems tight... 

What kind of things should I be looking for?

Does your 4-wheel drive still engage properly? You might have lost a birfield.

Does your 4-wheel drive still engage properly? You might have lost a birfield.

Hmmm...  I haven't used 4wd in a few weeks now.  The noise seems to have started after the last time I used it.

It's garaged right now and I won't be able to check until tomorrow evening after work..

Now for the really dumb questions...  What is a birfield?  How can you tell if a birfield is gone?  And if it doesn't engage in 4wd properly, how do I fix it?

Note:  I'm still pretty new to this Samurai stuff, so bear with me..