Are 1999-2004 Mustang IRS Rear Differentials and Gears The Same As Live Axle?
Kenny talks tech on the difference in the 1999-2004 Mustang Cobra IRS rear differentials, gears, and axles. Basically, the live axle and IRS differentials are the same, and so are the ring and pinion gears. Be careful though, the axle is not, so be sure you have the right differential to match the spline on the axles. 1999 and 2001 SVT Cobra Mustangs came with 28-spline axles, but 2003-2004 models came with 31-spline axles.