
Originally Posted by
niky
You want it engaged, so it doesn't slip IF water gets into the transmission housing.
Best to follow OTEP's advice in the other thread... when in doubt... DON'T.
Before you go out... hell... very first thing you should do with any car, is to open the engine bay and familiarize yourself with the layout of the engine bay... particularly the air-filter. Because that tells you what's safe and not safe to cross. Most cars have a hood-level air snorkel, facing forward. This means that as long as your headlights are out of the water, you can cross... as long as trucks don't throw waves at the hood.
Some cars, including some crossovers (CR-V for one) have the air snorkel at bumper level. That means that bumper-level water is a no-no. Even if these are protected from bow-waves coming off of trucks (as in the CR-V, it's buried inside the bumper with a small air pocket to supply it if the bumper gets submerged), if you're crossing long sections of deep water, you're a dead duck come halfway.
The worst of these I've seen are on the old Lancer and the Optra... behind the bumper, open to the engine bay, facing forward. Terrible in a flood, even if the intake resonators give you some running time before the engine stops.
Safest, with the highest fording capability, are certain pickups that draw air from the inner fender to the side. This puts the snorkel out of the way of bow-waves, and gives them a big pocket of air to draw from. These will not begin sucking up large amounts of water until the water is close to your hood.
But once the water is over the hood of any car, the amount of time that you can safely run the engine is very VERY limited. And if there's a current, even water halfway up the doors can carry you away. So even if you're confident your car can make it, it's always best to err on the side of caution and find a high spot and wait out the flood.
Better a few hours late than on-time behind a tow-truck...