i have a faint noise coming from rear end, i was planning on having gears installed, and was wandering if i have $1200 to spend could i get a new rear end with 3.73 gers,and what would be possible good upgrade to the rear

 

i have a 99 gt with k&n c.a.i. accufab 70mm tb and intake plenum, ported heads(30cc) frpp headers, bassani catted x-pipes, magnaflow cat back, i just replaced rotors and pads, and rear calipers, had the noise before this and was hoping it would fix that noise, someone said something about a recall on a spindel, but not sure what or where that is

 

What kind of noise are we hearing from the rear end , CLUNK, OR GRINDING, HUMMING NOISE?

 

its a faint grinding noise, i hear mostly between 25 to 45 mph sometimes louder than other times