I had a friend who serviced fd pagers. When someone called and said they dropped their pager into water he'd ask, "Toilet (ie. fresh water)? Bring it in and I'll look at it. Ocean (ie. salt water)? Who do I bill the new pager to?"
Either way I'd consider the truck totaled. Remember the adjusters don't pay out of their own pocket, but I've been told they have a monthly budget and if they routinely exceed their budget, it's reflected in their job performance reviews. Don't let the adjuster bully you just to get a gold star at his next review.