07 Hilux Double Cab Rear Differential Gearbox

[kobe8]

Hi guys, there's a problem over here with my 07 model double cab hilux.

I drove the LUX through a pool of water and I felt the impact from the water on the chassis of my lux..

I suspect that the impact has caused my rear gearbox to turn faulty, causing a flipping sound from the gearbox that got louder as the speed of the vehicle increases.

I wonder whats wrong with the gearbox, or is there anyone that has experienced the same situation as mine?

Thanks!