As far as it goes I have a 1997 legacy awd wagon I removed the rear CV axles in it for a flat track race but it lost all power (will mive foward and backward but has half the power of awd) with the CVS and drive shaft out it did not change the only way to make you awd if its a manual trans to a fwd you have to weld the center differential its a process but it can be done. And when I removed the drive shaft the grinding noise stopped so I'm sure the rear diff is bad