Hard to find transmission leak
 

Hi all,
I have a 95 4.3 4x4. I have discovered a leak of what I think is transmission fluid coming from the right side of the engine up by where the engine and transmission meet. The leak is not constant. It only leaks while driving and even then not always. But when it does, it leaks onto the hot exhaust and emits a lot of white smoke! I haven't been able to find a source of this leak. Its not coming from the pan, it looks to be coming from higher up on the right front end of the transmission. The fluids levels are all good right now.
It also causes smoke to come up and out of the back of the engine bay on the right side. Any Ideas would be greatly appreciated!
Thanks,

If it were the cooler lines, I would think it would leak all of the time, not just some of the time. If it were leaking out of the breather tube, it would normally leak down the driver side.

Is it coming out the transfer case breather tube that is attached to the transmission dip stick tube? If so, the likely cause is a bad front seal on the transfer case causing transmission fluid to over fill the transfer case pushing fluid up the breather tube.