LOUD noise when slowing down.

[east_sidaz40]

i was driving really fast about 130mph and tried to slow down kinda quickly and i heard this loud noise from my rear end as i was shifting down and applying my breaks. yes i do have 3.73 is this noise normal?
should i worry

 

[csledd]

what rpm did you shift down at?

 

[east_sidaz40]

no i never shift down that hard. I'm just saying that i was doing it also , but thats not why. i was mainly pushing down the breaks kinda hard .
so is that normal? the sound i mean