If the rear is an 8.8 you can buy the clutch pack from Summit for about $50 and they take about half an hour to change if the preload spring doesn't screw you to badly. If it's a 9.75, it is worth your money to have someone do it. The Eaton is a great upgrade, but once I put the clutches in mine the right way (Ford does it wierd) it has given me no further trouble.