This is exactly the kind of actionable advice I was looking for. Many thanks.It is most likely fluid coming out of the vent tube. This could be caused by several things. Most likely things are overfilled fluid or clogged cooler. Fluid probably got a little hot on the climb and vented out. It doesn't take much hitting the exhaust to make a lot of smoke. Also, check transfer case fluid level since the vent tubes are teed together. Fluid can leak from the trans to the transfer case causing transfer case to be overfilled.