Fact: You concluded your initial post by staying you don't want people criticizing you for acting stupid. You called this "normal driving", but the truth is it isn't. There's a reason roads are closed when several inches of water accumulate on them. 6 inches is enough to flood a car. 35 mph is fast enough to hydroplane a vehicle. This is why the mantra is, "Slow down. Go around." In case you missed it, here's a link to remind you.
https://www.weather.gov/tsa/hydro_tadd
Reality: It's not you who should be disappointed in the truck. It's the truck that should be disappointed in the owner/driver. If only they were animated and had feelings and the ability to communicate.
Solution:
Step1) Rebuild the engine. Inspect parts for damage, such as piston rods, bearings, etc. Air compresses. Water doesn't. Something bent or broke.
Step 2) Make better driving decisions going forward.
FYI, before you criticize me for my reply, realize that I've been there and done this myself. I was in a car, and the wake of a passing lifted truck rose the water enough to be sucked up into the intake. I was going slower than you, but I made the decision to go through the water anyways. I was ultimately responsible for that decision. I never blamed the manufacturer for building a crappy product, because they didn't. When this happened I was living in a coastal town that flooded every time it rains during high tide. And, it liked to rain a lot during high tide. I've seen flood waters that drowned semi trucks.