Here’s an interesting photo showing an early water fording test from the Baltimore Sun archives.
“JEEP GETS WATER TEST: LT JOHN CULLAR, OF OAKLAND, CALIF, TESTS A JEEP FOR ITS AMPHIBIOUS POSSIBILITIES EXPOSED PARTS SUCH AS THE MANIFOLD, THE CARBURATOR, INTAKE AND OIL BREATHER PIPE ARE SEALED AND EXTENDED UPWARD; THUS PREVENTING THE DANGEROUS POSSIBILITY OF SALT WATER SEEPING. LT CULLAR IS A MEMBER OF THE VETERAN AMERICAL DIVISION.”