2013 Detroit, RT40-4N, Axle Assemblies, Rear, Part Type: Complete Rear Axle Model: RT-40-4N Part #771AAC-A0898157 Condition: Good, Used Good Working Many more parts available from this unit!, Axle Spline Count: 10, Serial#: 771AAC-A089815T, Ratio: 2.79, Casting#: 472903S0128121