The rear is plenty big enough for most applications, so the materials and setup of the gears are the variables. Proper setup can mean a long or short life. I hammer mine pretty good, and I am sure the transbrake, 900 hp and 3050 lbs combined with 15 inch wide slicks really put it to the test! The 4.56 gears I have in mine have about 300 passes on them, no problems. Of all the things that can hurt a rear, the shock loads of a transbrake is tops.