I am not an expert, but i would do the following:
-Take carpets out - have em wahed
-have the rig power washed
-get the hisas grased
-check the oils (gear,axles,engine) for water contamination
-check the electricals if they are working OK
-check for any components of gearbox that may have any inlet for water (1kz 4x4 engage motor has it) and ensure that its water free
-have the whole unbderbelley spayed with clean oil for any potential rusting
-after a few days, have the rig power washed again
This is what i do when i get in contact with water