If you have driven your vehicle in deep water after the vehicle has warmed up, a couple of things may need to be looked at.

If the air vents in the transmission and differential(s) went underwater, the cooler water will probably cool the trans and /or differential(s) enough to suck in water. Particularly bad for live axle (non-irs) vehicles as the air volume in the axle is much greater.

If you vehicle was prepped for deep water, typically 4x4 trucks, there may not be an issue as they usually put the vents on extended tubes.

If you don't drive it enough to evaporate the water out of the transmission fluid or gear lube, it might be ugly later.

Also, if you have parked your vehicle in deep water, after some time you might find the axle bearings going bad, particularly in live axle vehicles. Water and grease don't mix well

So make sure you do proper maintenance after the flood.

If the vehicle has been submerged to a point where water has got into your transmissions or diffs you need to flush them through.

You can flush auto trans yourself through the cooler lines just remove the return line at the radiator and let it run in neutral.

Keep adding fluid until it comes out the same color as it is going in.

Many other joints and things on the car/truck will need a strip down clean and re-greasing.

While your carpets and seats are drying out, cut the legs down on a plastic chair and super glue it to the floor for driving around temporally..