Hi,

The front diff and rear trans have small 1/4" black plastic vent pipes that
run up to about 6" above floor level.  Trans vent goes up into top of engine
area, front diff reaches up into area ahead of gear shift.  Check these
because with age they make crack at the connection on the case. I think that
water will have filled the distributer by the time the tops of these go
under, you'll have wet feet at least.

Unimogs (and Hummers) do pressurise the diff to keep water out, if you are
this nutso scrounge the electric door lock air-pump from an Audi and hook it
up? Nice to have good seals at the output flanges, shame to push all the oil
out!  This is where you may get some seepage of water in BTW. VW says drive
steadily through 30cm (12") water, for 40cm (16") let the engine/exhaust
cool then drive through and check for water in engine once on other side.
Don't shift gears, the clutch may spin if wet. These depths apply to
non-Syncros and loafs also.

Derek Drew has driven to top of turn signal depth, on 27/8.5/14 tires,
likely about ~20" depth, I guess same here.  I quit when water starts coming
into the foot wells, want to keep the carpets dry. Some day I need a
volunteer to lie in the back with the engine lid off and watch what goes on
in deeper waters.  In front engined 4x4 a bit of speed sets up a bow wave
with a hollow behind it where the engine lurks, dunno what a vanagon does,
so I drive very slowly, while the exhaust burbles happily.  Like Bjorn said,
steam everywhere.

bye, Tim