Differancial Problem? Help. . . .

Hey guys. . .
Im new to the forum. I have a 1996 Camaro that I bought for 1400 bucks with 193k miles. It didnt turn on and had it towed to my home. I found out the engine needed to be completely rebuilt and I did that. It ran good for a while then I lost complete control and hydroplaned into a sidewalk. Spindle messed up with no body damage. I replaced all 4 tires and NOW i hear a funny noise that was not there before.

Problem:
Its a 5-spd and when I drive above 40 mph i hear a screeching noise on and off. Its not too loud but noticeable. Someone told me its the differencial that might need replacing or just the something in it. . . cant remember the name exactly. Can anyone help me out and confirm this?

Please don't post dupicate threads

Thanks